feat: add dart code for chapter_stack_and_queue and chapter_hashing (#445)
* feat: add dart code for chapter stack and queue * feat: add dart code for chapter_hashing * Update array_hash_map.dart
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codes/dart/chapter_hashing/array_hash_map.dart
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126
codes/dart/chapter_hashing/array_hash_map.dart
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/**
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* File: array_hash_map.dart
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* Created Time: 2023-03-29
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* Author: liuyuxin (gvenusleo@gmail.com)
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*/
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/* 键值对 int -> String */
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class Entry {
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int key;
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String val;
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Entry(this.key, this.val);
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}
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/* 基于数组简易实现的哈希表 */
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class ArrayHashMap {
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late List<Entry?> _buckets;
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ArrayHashMap() {
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// 初始化数组，包含 100 个桶
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_buckets = List.filled(100, null);
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}
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/* 哈希函数 */
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int _hashFunc(int key) {
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final int index = key % 100;
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return index;
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}
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/* 查询操作 */
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String? get(int key) {
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final int index = _hashFunc(key);
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final Entry? pair = _buckets[index];
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if (pair == null) {
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return null;
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}
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return pair.val;
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}
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/* 添加操作 */
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void put(int key, String val) {
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final Entry pair = Entry(key, val);
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final int index = _hashFunc(key);
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_buckets[index] = pair;
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}
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/* 删除操作 */
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void remove(int key) {
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final int index = _hashFunc(key);
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_buckets[index] = null;
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}
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/* 获取所有键值对 */
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List<Entry> entrySet() {
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List<Entry> entrySet = [];
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for (final Entry? pair in _buckets) {
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if (pair != null) {
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entrySet.add(pair);
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}
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}
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return entrySet;
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}
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/* 获取所有键 */
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List<int> keySet() {
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List<int> keySet = [];
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for (final Entry? pair in _buckets) {
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if (pair != null) {
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keySet.add(pair.key);
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}
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}
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return keySet;
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}
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/* 获取所有值 */
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List<String> values() {
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List<String> valueSet = [];
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for (final Entry? pair in _buckets) {
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if (pair != null) {
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valueSet.add(pair.val);
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}
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}
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return valueSet;
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}
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/* 打印哈希表 */
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void printHashMap() {
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for (final Entry kv in entrySet()) {
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print("${kv.key} -> ${kv.val}");
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}
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}
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}
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/* Driver Code */
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void main() {
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/* 初始化哈希表 */
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final ArrayHashMap map = ArrayHashMap();
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/* 添加操作 */
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// 在哈希表中添加键值对 (key, value)
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map.put(12836, "小哈");
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map.put(15937, "小啰");
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map.put(16750, "小算");
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map.put(13276, "小法");
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map.put(10583, "小鸭");
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print("\n添加完成后，哈希表为\nKey -> Value");
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map.printHashMap();
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/* 查询操作 */
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// 向哈希表输入键 key ，得到值 value
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String? name = map.get(15937);
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print("\n输入学号 15937 ，查询到姓名 $name");
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/* 删除操作 */
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// 在哈希表中删除键值对 (key, value)
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map.remove(10583);
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print("\n删除 10583 后，哈希表为\nKey -> Value");
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map.printHashMap();
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/* 遍历哈希表 */
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print("\n遍历键值对 Key->Value");
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map.entrySet().forEach((kv) => print("${kv.key} -> ${kv.val}"));
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print("\n单独遍历键 Key");
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map.keySet().forEach((key) => print("$key"));
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print("\n单独遍历值 Value");
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map.values().forEach((val) => print("$val"));
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}
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40
codes/dart/chapter_hashing/hash_map.dart
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40
codes/dart/chapter_hashing/hash_map.dart
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/**
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* File: hash_map.dart
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* Created Time: 2023-03-29
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* Author: liuyuxin (gvenusleo@gmail.com)
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*/
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/* Driver Code */
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void main() {
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/* 初始化哈希表 */
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final Map<int, String> map = {};
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/* 添加操作 */
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// 在哈希表中添加键值对 (key, value)
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map[12836] = "小哈";
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map[15937] = "小啰";
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map[16750] = "小算";
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map[13276] = "小法";
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map[10583] = "小鸭";
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print("\n添加完成后，哈希表为\nKey -> Value");
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map.forEach((key, value) => print("$key -> $value"));
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/* 查询操作 */
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// 向哈希表输入键 key ，得到值 value
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final String? name = map[15937];
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print("\n输入学号 15937 ，查询到姓名 $name");
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/* 删除操作 */
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// 在哈希表中删除键值对 (key, value)
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map.remove(10583);
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print("\n删除 10583 后，哈希表为\nKey -> Value");
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map.forEach((key, value) => print("$key -> $value"));
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/* 遍历哈希表 */
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print("\n遍历键值对 Key->Value");
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map.forEach((key, value) => print("$key -> $value"));
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print("\n单独遍历键 Key");
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map.forEach((key, value) => print("$key"));
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print("\n单独遍历值 Value");
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map.forEach((key, value) => print("$value"));
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}
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146
codes/dart/chapter_stack_and_queue/array_deque.dart
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146
codes/dart/chapter_stack_and_queue/array_deque.dart
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/**
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* File: array_deque.dart
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* Created Time: 2023-03-28
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* Author: liuyuxin (gvenusleo@gmail.com)
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*/
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/* 基于环形数组实现的双向队列 */
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class ArrayDeque {
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late List<int> _nums; // 用于存储双向队列元素的数组
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late int _front; // 队首指针，指向队首元素
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late int _queSize; // 双向队列长度
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/* 构造方法 */
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ArrayDeque(int capacity) {
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this._nums = List.filled(capacity, 0);
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this._front = this._queSize = 0;
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}
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/* 获取双向队列的容量 */
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int capacity() {
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return _nums.length;
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}
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/* 获取双向队列的长度 */
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int size() {
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return _queSize;
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}
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/* 判断双向队列是否为空 */
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bool isEmpty() {
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return _queSize == 0;
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}
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/* 计算环形数组索引 */
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int index(int i) {
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// 通过取余操作实现数组首尾相连
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// 当 i 越过数组尾部后，回到头部
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// 当 i 越过数组头部后，回到尾部
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return (i + capacity()) % capacity();
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}
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/* 队首入队 */
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void pushFirst(int num) {
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if (_queSize == capacity()) {
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throw Exception("双向队列已满");
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}
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// 队首指针向左移动一位
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// 通过取余操作，实现 _front 越过数组头部后回到尾部
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_front = index(_front - 1);
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// 将 num 添加至队首
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_nums[_front] = num;
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_queSize++;
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}
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/* 队尾入队 */
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void pushLast(int num) {
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if (_queSize == capacity()) {
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throw Exception("双向队列已满");
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}
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// 计算尾指针，指向队尾索引 + 1
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int rear = index(_front + _queSize);
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// 将 num 添加至队尾
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_nums[rear] = num;
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_queSize++;
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}
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/* 队首出队 */
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int popFirst() {
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int num = peekFirst();
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// 队首指针向右移动一位
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_front = index(_front + 1);
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_queSize--;
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return num;
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}
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/* 队尾出队 */
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int popLast() {
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int num = peekLast();
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_queSize--;
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return num;
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}
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/* 访问队首元素 */
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int peekFirst() {
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if (isEmpty()) {
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throw Exception("双向队列为空");
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}
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return _nums[_front];
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}
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/* 访问队尾元素 */
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int peekLast() {
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if (isEmpty()) {
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throw Exception("双向队列为空");
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}
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// 计算尾元素索引
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int last = index(_front + _queSize - 1);
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return _nums[last];
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}
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/* 返回数组用于打印 */
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List<int> toArray() {
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// 仅转换有效长度范围内的列表元素
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List<int> res = List.filled(_queSize, 0);
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for (int i = 0, j = _front; i < _queSize; i++, j++) {
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res[i] = _nums[index(j)];
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}
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return res;
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}
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}
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/* Driver Code */
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void main() {
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/* 初始化双向队列 */
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final ArrayDeque deque = ArrayDeque(10);
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deque.pushLast(3);
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deque.pushLast(2);
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deque.pushLast(5);
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print("双向队列 deque = ${deque.toArray()}");
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/* 访问元素 */
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final int peekFirst = deque.peekFirst();
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print("队首元素 peekFirst = $peekFirst");
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final int peekLast = deque.peekLast();
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print("队尾元素 peekLast = $peekLast");
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/* 元素入队 */
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deque.pushLast(4);
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print("元素 4 队尾入队后 deque = ${deque.toArray()}");
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deque.pushFirst(1);
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print("元素 1 队首入队后 deque = ${deque.toArray()}");
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/* 元素出队 */
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final int popLast = deque.popLast();
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print("队尾出队元素 = $popLast，队尾出队后 deque = ${deque.toArray()}");
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final int popFirst = deque.popFirst();
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print("队首出队元素 = $popFirst，队首出队后 deque = ${deque.toArray()}");
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/* 获取双向队列的长度 */
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final int size = deque.size();
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print("双向队列的长度 size = $size");
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/* 判断双向队列是否为空 */
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final bool isEmpty = deque.isEmpty();
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print("双向队列是否为空 = $isEmpty");
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}
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110
codes/dart/chapter_stack_and_queue/array_queue.dart
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110
codes/dart/chapter_stack_and_queue/array_queue.dart
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/**
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* File: array_queue.dart
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* Created Time: 2023-03-28
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* Author: liuyuxin (gvenusleo@gmail.com)
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*/
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/* 基于环形数组实现的队列 */
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class ArrayQueue {
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late List<int> _nums; // 用于储存队列元素的数组
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late int _front; // 队首指针，指向队首元素
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late int _queSize; // 队列长度
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ArrayQueue(int capacity) {
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_nums = List.filled(capacity, 0);
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_front = _queSize = 0;
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}
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/* 获取队列的容量 */
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int capaCity() {
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return _nums.length;
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}
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/* 获取队列的长度 */
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int size() {
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return _queSize;
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}
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/* 判断队列是否为空 */
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bool isEmpty() {
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return _queSize == 0;
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}
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/* 入队 */
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void push(int num) {
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if (_queSize == capaCity()) {
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throw Exception("队列已满");
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}
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// 计算尾指针，指向队尾索引 + 1
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// 通过取余操作，实现 rear 越过数组尾部后回到头部
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int rear = (_front + _queSize) % capaCity();
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// 将 num 添加至队尾
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_nums[rear] = num;
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_queSize++;
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}
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/* 出队 */
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int pop() {
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int num = peek();
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// 队首指针向后移动一位，若越过尾部则返回到数组头部
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_front = (_front + 1) % capaCity();
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_queSize--;
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return num;
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}
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/* 访问队首元素 */
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int peek() {
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if (isEmpty()) {
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throw Exception("队列为空");
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}
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return _nums[_front];
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}
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/* 返回 Array */
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List<int> toArray() {
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// 仅转换有效长度范围内的列表元素
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final List<int> res = List.filled(_queSize, 0);
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for (int i = 0, j = _front; i < _queSize; i++, j++) {
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res[i] = _nums[j % capaCity()];
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}
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return res;
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}
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}
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/* Driver Code */
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void main() {
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/* 初始化队列 */
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final int capacity = 10;
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final ArrayQueue queue = ArrayQueue(capacity);
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/* 元素入队 */
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queue.push(1);
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queue.push(3);
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queue.push(2);
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queue.push(5);
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queue.push(4);
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print("队列 queue = ${queue.toArray()}");
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/* 访问队首元素 */
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final int peek = queue.peek();
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print("队首元素 peek = $peek");
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/* 元素出队 */
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final int pop = queue.pop();
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print("出队元素 pop = $pop，出队后 queue = ${queue.toArray()}");
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/* 获取队列长度 */
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final int size = queue.size();
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print("队列长度 size = $size");
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/* 判断队列是否为空 */
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final bool isEmpty = queue.isEmpty();
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print("队列是否为空 isEmpty = $isEmpty");
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/* 测试环形数组 */
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for (int i = 0; i < 10; i++) {
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queue.push(i);
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queue.pop();
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print("第 $i 轮入队 + 出队后 queue = ${queue.toArray()}");
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}
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}
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77
codes/dart/chapter_stack_and_queue/array_stack.dart
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77
codes/dart/chapter_stack_and_queue/array_stack.dart
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/**
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* File: array_stack.dart
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* Created Time: 2023-03-28
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* Author: liuyuxin (gvenusleo@gmail.com)
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*/
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/* 基于数组实现的栈 */
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class ArrayStack {
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late List<int> _stack;
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ArrayStack() {
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_stack = [];
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}
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/* 获取栈的长度 */
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int size() {
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return _stack.length;
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}
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/* 判断栈是否为空 */
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bool isEmpty() {
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return _stack.isEmpty;
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}
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/* 入栈 */
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void push(int num) {
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_stack.add(num);
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}
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/* 出栈 */
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int pop() {
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if (isEmpty()) {
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throw Exception("栈为空");
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}
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return _stack.removeLast();
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}
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/* 访问栈顶元素 */
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int peek() {
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||||
if (isEmpty()) {
|
||||
throw Exception("栈为空");
|
||||
}
|
||||
return _stack.last;
|
||||
}
|
||||
|
||||
/* 将栈转化为 Array 并返回 */
|
||||
List<int> toArray() => _stack;
|
||||
}
|
||||
|
||||
/* Driver Code */
|
||||
void main() {
|
||||
/* 初始化栈 */
|
||||
final ArrayStack stack = ArrayStack();
|
||||
|
||||
/* 元素入栈 */
|
||||
stack.push(1);
|
||||
stack.push(3);
|
||||
stack.push(2);
|
||||
stack.push(5);
|
||||
stack.push(4);
|
||||
print("栈 stack = ${stack.toArray()}");
|
||||
|
||||
/* 访问栈顶元素 */
|
||||
final int peek = stack.peek();
|
||||
print("栈顶元素 peek = $peek");
|
||||
|
||||
/* 元素出栈 */
|
||||
final int pop = stack.pop();
|
||||
print("出栈元素 pop = $pop，出栈后 stack = ${stack.toArray()}");
|
||||
|
||||
/* 获取栈的长度 */
|
||||
final int size = stack.size();
|
||||
print("栈的长度 size = $size");
|
||||
|
||||
/* 判断是否为空 */
|
||||
final bool isEmpty = stack.isEmpty();
|
||||
print("栈是否为空 = $isEmpty");
|
||||
}
|
||||
40
codes/dart/chapter_stack_and_queue/deque.dart
Normal file
40
codes/dart/chapter_stack_and_queue/deque.dart
Normal file
@ -0,0 +1,40 @@
|
||||
/**
|
||||
* File: deque.dart
|
||||
* Created Time: 2023-03-28
|
||||
* Author: liuyuxin (gvenusleo@gmail.com)
|
||||
*/
|
||||
|
||||
import 'dart:collection';
|
||||
|
||||
void main() {
|
||||
/* 初始化双向队列 */
|
||||
final Queue<int> deque = Queue();
|
||||
|
||||
/* 元素入队 */
|
||||
deque.addLast(2);
|
||||
deque.addLast(5);
|
||||
deque.addLast(4);
|
||||
deque.addFirst(3);
|
||||
deque.addFirst(1);
|
||||
print("双向队列 deque = $deque");
|
||||
|
||||
/* 访问元素 */
|
||||
final int peekFirst = deque.first;
|
||||
print("队首元素 peekFirst = $peekFirst");
|
||||
final int peekLast = deque.last;
|
||||
print("队尾元素 peekLast = $peekLast");
|
||||
|
||||
/* 元素出队 */
|
||||
final int popFirst = deque.removeFirst();
|
||||
print("队首出队元素 popFirst = $popFirst，队首出队后 deque = $deque");
|
||||
final int popLast = deque.removeLast();
|
||||
print("队尾出队元素 popLast = $popLast，队尾出队后 deque = $deque");
|
||||
|
||||
/* 获取双向队列的长度 */
|
||||
final int size = deque.length;
|
||||
print("双向队列的长度 size = $size");
|
||||
|
||||
/* 判断双向队列是否为空 */
|
||||
final bool isEmpty = deque.isEmpty;
|
||||
print("双向队列是否为空 isEmpty = $isEmpty");
|
||||
}
|
||||
167
codes/dart/chapter_stack_and_queue/linkedlist_deque.dart
Normal file
167
codes/dart/chapter_stack_and_queue/linkedlist_deque.dart
Normal file
@ -0,0 +1,167 @@
|
||||
/**
|
||||
* File: linkedlist_deque.dart
|
||||
* Created Time: 2023-03-28
|
||||
* Author: liuyuxin (gvenusleo@gmail.com)
|
||||
*/
|
||||
|
||||
/* 双向链表结点 */
|
||||
class ListNode {
|
||||
int val; // 结点值
|
||||
ListNode? next; // 后继结点引用（指针）
|
||||
ListNode? prev; // 前驱结点引用（指针）
|
||||
|
||||
ListNode(this.val, {this.next, this.prev});
|
||||
}
|
||||
|
||||
/* 基于双向链表实现的双向对列 */
|
||||
class LinkedListDeque {
|
||||
late ListNode? _front; // 头结点 _front
|
||||
late ListNode? _rear; // 尾结点 _rear
|
||||
int _queSize = 0; // 双向队列的长度
|
||||
|
||||
LinkedListDeque() {
|
||||
this._front = null;
|
||||
this._rear = null;
|
||||
}
|
||||
|
||||
/* 获取双向队列长度 */
|
||||
int size() {
|
||||
return this._queSize;
|
||||
}
|
||||
|
||||
/* 判断双向队列是否为空 */
|
||||
bool isEmpty() {
|
||||
return size() == 0;
|
||||
}
|
||||
|
||||
/* 入队操作 */
|
||||
void push(int num, bool isFront) {
|
||||
final ListNode node = ListNode(num);
|
||||
if (isEmpty()) {
|
||||
// 若链表为空，则令 _front，_rear 都指向 node
|
||||
_front = _rear = node;
|
||||
} else if (isFront) {
|
||||
// 队首入队操作
|
||||
// 将 node 添加至链表头部
|
||||
_front!.prev = node;
|
||||
node.next = _front;
|
||||
_front = node; // 更新头结点
|
||||
} else {
|
||||
// 队尾入队操作
|
||||
// 将 node 添加至链表尾部
|
||||
_rear!.next = node;
|
||||
node.prev = _rear;
|
||||
_rear = node; // 更新尾结点
|
||||
}
|
||||
_queSize++; // 更新队列长度
|
||||
}
|
||||
|
||||
/* 队首入队 */
|
||||
void pushFirst(int num) {
|
||||
push(num, true);
|
||||
}
|
||||
|
||||
/* 队尾入队 */
|
||||
void pushLast(int num) {
|
||||
push(num, false);
|
||||
}
|
||||
|
||||
/* 出队操作 */
|
||||
int? pop(bool isFront) {
|
||||
// 若队列为空，直接返回 null
|
||||
if (isEmpty()) {
|
||||
return null;
|
||||
}
|
||||
final int val;
|
||||
if (isFront) {
|
||||
// 队首出队操作
|
||||
val = _front!.val; // 暂存头结点值
|
||||
// 删除头结点
|
||||
ListNode? fNext = _front!.next;
|
||||
if (fNext != null) {
|
||||
fNext.prev = null;
|
||||
_front!.next = null;
|
||||
}
|
||||
_front = fNext; // 更新头结点
|
||||
} else {
|
||||
// 队尾出队操作
|
||||
val = _rear!.val; // 暂存尾结点值
|
||||
// 删除尾结点
|
||||
ListNode? rPrev = _rear!.prev;
|
||||
if (rPrev != null) {
|
||||
rPrev.next = null;
|
||||
_rear!.prev = null;
|
||||
}
|
||||
_rear = rPrev; // 更新尾结点
|
||||
}
|
||||
_queSize--; // 更新队列长度
|
||||
return val;
|
||||
}
|
||||
|
||||
/* 队首出队 */
|
||||
int? popFirst() {
|
||||
return pop(true);
|
||||
}
|
||||
|
||||
/* 队尾出队 */
|
||||
int? popLast() {
|
||||
return pop(false);
|
||||
}
|
||||
|
||||
/* 访问队首元素 */
|
||||
int? peekFirst() {
|
||||
return _front?.val;
|
||||
}
|
||||
|
||||
/* 访问队尾元素 */
|
||||
int? peekLast() {
|
||||
return _rear?.val;
|
||||
}
|
||||
|
||||
/* 返回数组用于打印 */
|
||||
List<int> toArray() {
|
||||
ListNode? node = _front;
|
||||
final List<int> res = [];
|
||||
for (int i = 0; i < _queSize; i++) {
|
||||
res.add(node!.val);
|
||||
node = node.next;
|
||||
}
|
||||
return res;
|
||||
}
|
||||
}
|
||||
|
||||
/* Driver Code */
|
||||
void main() {
|
||||
/* 初始化双向队列 */
|
||||
final LinkedListDeque deque = LinkedListDeque();
|
||||
deque.pushLast(3);
|
||||
deque.pushLast(2);
|
||||
deque.pushLast(5);
|
||||
print("双向队列 deque = ${deque.toArray()}");
|
||||
|
||||
/* 访问元素 */
|
||||
int? peekFirst = deque.peekFirst();
|
||||
print("队首元素 peekFirst = $peekFirst");
|
||||
int? peekLast = deque.peekLast();
|
||||
print("队尾元素 peekLast = $peekLast");
|
||||
|
||||
/* 元素入队 */
|
||||
deque.pushLast(4);
|
||||
print("元素 4 队尾入队后 deque = ${deque.toArray()}");
|
||||
deque.pushFirst(1);
|
||||
print("元素 1 队首入队后 deque = ${deque.toArray()}");
|
||||
|
||||
/* 元素出队 */
|
||||
int? popLast = deque.popLast();
|
||||
print("队尾出队元素 = $popLast，队尾出队后 deque = ${deque.toArray()}");
|
||||
int? popFirst = deque.popFirst();
|
||||
print("队首出队元素 = $popFirst，队首出队后 deque = ${deque.toArray()}");
|
||||
|
||||
/* 获取双向队列的长度 */
|
||||
int size = deque.size();
|
||||
print("双向队列长度 size = $size");
|
||||
|
||||
/* 判断双向队列是否为空 */
|
||||
bool isEmpty = deque.isEmpty();
|
||||
print("双向队列是否为空 = $isEmpty");
|
||||
}
|
||||
103
codes/dart/chapter_stack_and_queue/linkedlist_queue.dart
Normal file
103
codes/dart/chapter_stack_and_queue/linkedlist_queue.dart
Normal file
@ -0,0 +1,103 @@
|
||||
/**
|
||||
* File: linkedlist_queue.dart
|
||||
* Created Time: 2023-03-28
|
||||
* Author: liuyuxin (gvenusleo@gmail.com)
|
||||
*/
|
||||
|
||||
import '../utils/list_node.dart';
|
||||
|
||||
/* 基于链表实现的队列 */
|
||||
class LinkedListQueue {
|
||||
ListNode? _front; // 头结点 _front
|
||||
ListNode? _rear; // 尾结点 _rear
|
||||
int _queSize = 0; // 队列长度
|
||||
|
||||
LinkedListQueue() {
|
||||
_front = null;
|
||||
_rear = null;
|
||||
}
|
||||
|
||||
/* 获取队列的长度 */
|
||||
int size() {
|
||||
return _queSize;
|
||||
}
|
||||
|
||||
/* 判断队列是否为空 */
|
||||
bool isEmpty() {
|
||||
return _queSize == 0;
|
||||
}
|
||||
|
||||
/* 入队 */
|
||||
void push(int num) {
|
||||
// 尾结点后添加 num
|
||||
final node = ListNode(num);
|
||||
// 如果队列为空，则令头、尾结点都指向该结点
|
||||
if (_front == null) {
|
||||
_front = node;
|
||||
_rear = node;
|
||||
} else {
|
||||
// 如果队列不为空，则将该结点添加到尾结点后
|
||||
_rear!.next = node;
|
||||
_rear = node;
|
||||
}
|
||||
_queSize++;
|
||||
}
|
||||
|
||||
/* 出队 */
|
||||
int pop() {
|
||||
final int num = peek();
|
||||
// 删除头结点
|
||||
_front = _front!.next;
|
||||
_queSize--;
|
||||
return num;
|
||||
}
|
||||
|
||||
/* 访问队首元素 */
|
||||
int peek() {
|
||||
if (_queSize == 0) {
|
||||
throw Exception('队列为空');
|
||||
}
|
||||
return _front!.val;
|
||||
}
|
||||
|
||||
/* 将链表转化为 Array 并返回 */
|
||||
List<int> toArray() {
|
||||
ListNode? node = _front;
|
||||
final List<int> queue = [];
|
||||
while (node != null) {
|
||||
queue.add(node.val);
|
||||
node = node.next;
|
||||
}
|
||||
return queue;
|
||||
}
|
||||
}
|
||||
|
||||
/* Driver Code */
|
||||
void main() {
|
||||
/* 初始化队列 */
|
||||
final queue = LinkedListQueue();
|
||||
|
||||
/* 元素入队 */
|
||||
queue.push(1);
|
||||
queue.push(3);
|
||||
queue.push(2);
|
||||
queue.push(5);
|
||||
queue.push(4);
|
||||
print("队列 queue = ${queue.toArray()}");
|
||||
|
||||
/* 访问队首元素 */
|
||||
final int peek = queue.peek();
|
||||
print("队首元素 peek = $peek");
|
||||
|
||||
/* 元素出队 */
|
||||
final int pop = queue.pop();
|
||||
print("出队元素 pop = $pop，出队后 queue = ${queue.toArray()}");
|
||||
|
||||
/* 获取队列的长度 */
|
||||
final int size = queue.size();
|
||||
print("队列长度 size = $size");
|
||||
|
||||
/* 判断队列是否为空 */
|
||||
final bool isEmpty = queue.isEmpty();
|
||||
print("队列是否为空 = $isEmpty");
|
||||
}
|
||||
93
codes/dart/chapter_stack_and_queue/linkedlist_stack.dart
Normal file
93
codes/dart/chapter_stack_and_queue/linkedlist_stack.dart
Normal file
@ -0,0 +1,93 @@
|
||||
/**
|
||||
* File: linkedlist_stack.dart
|
||||
* Created Time: 2023-03-27
|
||||
* Author: liuyuxin (gvenusleo@gmail.com)
|
||||
*/
|
||||
|
||||
import '../utils/list_node.dart';
|
||||
|
||||
/* 基于链表类实现的栈 */
|
||||
class LinkedListStack {
|
||||
ListNode? _stackPeek; // 将头节点作为栈顶
|
||||
int _stkSize = 0; // 栈的长度
|
||||
|
||||
LinkedListStack() {
|
||||
_stackPeek = null;
|
||||
}
|
||||
|
||||
/* 获取栈的长度 */
|
||||
int size() {
|
||||
return _stkSize;
|
||||
}
|
||||
|
||||
/* 判断栈是否为空 */
|
||||
bool isEmpty() {
|
||||
return _stkSize == 0;
|
||||
}
|
||||
|
||||
/* 入栈 */
|
||||
void push(int num) {
|
||||
final ListNode node = ListNode(num);
|
||||
node.next = _stackPeek;
|
||||
_stackPeek = node;
|
||||
_stkSize++;
|
||||
}
|
||||
|
||||
/* 出栈 */
|
||||
int pop() {
|
||||
final int num = peek();
|
||||
_stackPeek = _stackPeek!.next;
|
||||
_stkSize--;
|
||||
return num;
|
||||
}
|
||||
|
||||
/* 访问栈顶元素 */
|
||||
int peek() {
|
||||
if (_stackPeek == null) {
|
||||
throw Exception("栈为空");
|
||||
}
|
||||
return _stackPeek!.val;
|
||||
}
|
||||
|
||||
/* 将链表转化为 List 并返回 */
|
||||
List<int> toList() {
|
||||
ListNode? node = _stackPeek;
|
||||
List<int> list = [];
|
||||
while (node != null) {
|
||||
list.add(node.val);
|
||||
node = node.next;
|
||||
}
|
||||
list = list.reversed.toList();
|
||||
return list;
|
||||
}
|
||||
}
|
||||
|
||||
/* Driver Code */
|
||||
void main() {
|
||||
/* 初始化栈 */
|
||||
final LinkedListStack stack = LinkedListStack();
|
||||
|
||||
/* 元素入栈 */
|
||||
stack.push(1);
|
||||
stack.push(3);
|
||||
stack.push(2);
|
||||
stack.push(5);
|
||||
stack.push(4);
|
||||
print("栈 stack = ${stack.toList()}");
|
||||
|
||||
/* 访问栈顶元素 */
|
||||
final int peek = stack.peek();
|
||||
print("栈顶元素 peek = $peek");
|
||||
|
||||
/* 元素出栈 */
|
||||
final int pop = stack.pop();
|
||||
print("出栈元素 pop = $pop，出栈后 stack = ${stack.toList()}");
|
||||
|
||||
/* 获取栈的长度 */
|
||||
final int size = stack.size();
|
||||
print("栈的长度 size = $size");
|
||||
|
||||
/* 判断是否为空 */
|
||||
final bool isEmpty = stack.isEmpty();
|
||||
print("栈是否为空 = $isEmpty");
|
||||
}
|
||||
37
codes/dart/chapter_stack_and_queue/queue.dart
Normal file
37
codes/dart/chapter_stack_and_queue/queue.dart
Normal file
@ -0,0 +1,37 @@
|
||||
/**
|
||||
* File: queue:dart
|
||||
* Created Time: 2023-03-28
|
||||
* Author: liuyuxin (gvenusleo@gmail.com)
|
||||
*/
|
||||
|
||||
import 'dart:collection';
|
||||
|
||||
void main() {
|
||||
/* 初始化队列 */
|
||||
// 在 Dart 中，一般将双向队列类 Queue 看作队列使用
|
||||
final Queue<int> queue = Queue();
|
||||
|
||||
/* 元素入队 */
|
||||
queue.add(1);
|
||||
queue.add(3);
|
||||
queue.add(2);
|
||||
queue.add(5);
|
||||
queue.add(4);
|
||||
print("队列 queue = $queue");
|
||||
|
||||
/* 访问队首元素 */
|
||||
final int peek = queue.first;
|
||||
print("队首元素 peek = $peek");
|
||||
|
||||
/* 元素出队 */
|
||||
final int pop = queue.removeFirst();
|
||||
print("出队元素 pop = $pop，出队后队列 queue = $queue");
|
||||
|
||||
/* 获取队列长度 */
|
||||
final int size = queue.length;
|
||||
print("队列长度 size = $size");
|
||||
|
||||
/* 判断队列是否为空 */
|
||||
final bool isEmpty = queue.isEmpty;
|
||||
print("队列是否为空 isEmpty = $isEmpty");
|
||||
}
|
||||
36
codes/dart/chapter_stack_and_queue/stack.dart
Normal file
36
codes/dart/chapter_stack_and_queue/stack.dart
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/**
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* File: stack.dart
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* Created Time: 2023-03-27
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* Author: liuyuxin (gvenusleo@gmail.com)
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*/
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void main() {
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/* 初始化栈 */
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// Dart 没有内置的栈类，可以把 List 当作栈来使用
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final List<int> stack = [];
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/* 元素入栈 */
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stack.add(1);
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stack.add(3);
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stack.add(2);
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stack.add(5);
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stack.add(4);
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print("栈 stack = $stack");
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||||
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||||
/* 访问栈顶元素 */
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final int peek = stack.last;
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||||
print("栈顶元素 peek = $peek");
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||||
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/* 元素出栈 */
|
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final int pop = stack.removeLast();
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print("出栈元素 pop = $pop");
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print("出栈后 stack = $stack");
|
||||
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||||
/* 获取栈的长度 */
|
||||
final int size = stack.length;
|
||||
print("栈的长度 size = $size");
|
||||
|
||||
/* 判断是否为空 */
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||||
final bool isEmpty = stack.isEmpty;
|
||||
print("栈是否为空 = $isEmpty");
|
||||
}
|
||||
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