refactor: use global using to reduce usings in each file (#486)

codes/csharp/GlobalUsing.cs

@@ -0,0 +1,2 @@
+global using NUnit.Framework;
+global using hello_algo.utils;

codes/csharp/chapter_array_and_linkedlist/array.cs

@@ -2,8 +2,6 @@
 // Created Time: 2022-12-14
 // Author: mingXta (1195669834@qq.com)
 
-using NUnit.Framework;
-
 namespace hello_algo.chapter_array_and_linkedlist;
 
 public class array {

codes/csharp/chapter_array_and_linkedlist/linked_list.cs

@@ -2,9 +2,6 @@
 // Created Time: 2022-12-16
 // Author: mingXta (1195669834@qq.com)
 
-using hello_algo.utils;
-using NUnit.Framework;
-
 namespace hello_algo.chapter_array_and_linkedlist;
 
 public class linked_list {

codes/csharp/chapter_array_and_linkedlist/list.cs

@@ -4,8 +4,6 @@
  * Author: haptear (haptear@hotmail.com)
  */
 
-using NUnit.Framework;
-
 namespace hello_algo.chapter_array_and_linkedlist;
 
 public class list {

codes/csharp/chapter_array_and_linkedlist/my_list.cs

@@ -4,8 +4,6 @@
  * Author: haptear (haptear@hotmail.com)
  */
 
-using NUnit.Framework;
-
 namespace hello_algo.chapter_array_and_linkedlist;
 
 /* 列表类简易实现 */

codes/csharp/chapter_backtracking/n_queens.cs

@@ -4,9 +4,6 @@
  * Author: hpstory (hpstory1024@163.com)
  */
 
-using hello_algo.utils;
-using NUnit.Framework;
-
 namespace hello_algo.chapter_backtracking;
 
 public class n_queens {

codes/csharp/chapter_backtracking/permutations_i.cs

@@ -4,9 +4,6 @@
  * Author: hpstory (hpstory1024@163.com)
  */
 
-using hello_algo.utils;
-using NUnit.Framework;
-
 namespace hello_algo.chapter_backtracking;
 
 public class permutations_i {

codes/csharp/chapter_backtracking/permutations_ii.cs

@@ -4,9 +4,6 @@
  * Author: hpstory (hpstory1024@163.com)
  */
 
-using hello_algo.utils;
-using NUnit.Framework;
-
 namespace hello_algo.chapter_backtracking;
 
 public class permutations_ii {

codes/csharp/chapter_backtracking/preorder_traversal_i_compact.cs

@@ -4,9 +4,6 @@
  * Author: hpstory (hpstory1024@163.com)
  */
 
-using hello_algo.utils;
-using NUnit.Framework;
-
 namespace hello_algo.chapter_backtracking;
 
 public class preorder_traversal_i_compact {

codes/csharp/chapter_backtracking/preorder_traversal_ii_compact.cs

@@ -4,9 +4,6 @@
  * Author: hpstory (hpstory1024@163.com)
  */
 
-using hello_algo.utils;
-using NUnit.Framework;
-
 namespace hello_algo.chapter_backtracking;
 
 public class preorder_traversal_ii_compact {

codes/csharp/chapter_backtracking/preorder_traversal_iii_compact.cs

@@ -4,9 +4,6 @@
  * Author: hpstory (hpstory1024@163.com)
  */
 
-using hello_algo.utils;
-using NUnit.Framework;
-
 namespace hello_algo.chapter_backtracking;
 
 public class preorder_traversal_iii_compact {

codes/csharp/chapter_backtracking/preorder_traversal_iii_template.cs

@@ -4,9 +4,6 @@
  * Author: hpstory (hpstory1024@163.com)
  */
 
-using hello_algo.utils;
-using NUnit.Framework;
-
 namespace hello_algo.chapter_backtracking;
 
 public class preorder_traversal_iii_template {

codes/csharp/chapter_binary_search/binary_search.cs

@@ -4,8 +4,6 @@
  * Author: haptear (haptear@hotmail.com)
  */
 
-using NUnit.Framework;
-
 namespace hello_algo.chapter_binary_search;
 
 public class binary_search {

codes/csharp/chapter_computational_complexity/space_complexity.cs

@@ -4,9 +4,6 @@
  * Author: haptear (haptear@hotmail.com)
  */
 
-using hello_algo.utils;
-using NUnit.Framework;
-
 namespace hello_algo.chapter_computational_complexity;
 
 public class space_complexity {

codes/csharp/chapter_computational_complexity/time_complexity.cs

@@ -4,8 +4,6 @@
  * Author: haptear (haptear@hotmail.com)
  */
 
-using NUnit.Framework;
-
 namespace hello_algo.chapter_computational_complexity;
 
 public class time_complexity {

codes/csharp/chapter_computational_complexity/worst_best_time_complexity.cs

@@ -4,8 +4,6 @@
  * Author: haptear (haptear@hotmail.com)
  */
 
-using NUnit.Framework;
-
 namespace hello_algo.chapter_computational_complexity;
 
 public class worst_best_time_complexity {

codes/csharp/chapter_graph/graph_adjacency_list.cs

@@ -4,9 +4,6 @@
  * Author: zjkung1123 (zjkung1123@gmail.com)
  */
 
-using hello_algo.utils;
-using NUnit.Framework;
-
 namespace hello_algo.chapter_graph;
 
 /* 基于邻接表实现的无向图类 */

codes/csharp/chapter_graph/graph_adjacency_matrix.cs

@@ -4,9 +4,6 @@
  * Author: zjkung1123 (zjkung1123@gmail.com)
  */
 
-using hello_algo.utils;
-using NUnit.Framework;
-
 namespace hello_algo.chapter_graph;
 
 /* 基于邻接矩阵实现的无向图类 */

codes/csharp/chapter_graph/graph_bfs.cs

@@ -4,9 +4,6 @@
  * Author: hpstory (hpstory1024@163.com)
  */
 
-using hello_algo.utils;
-using NUnit.Framework;
-
 namespace hello_algo.chapter_graph;
 
 public class graph_bfs {

codes/csharp/chapter_graph/graph_dfs.cs

@@ -4,9 +4,6 @@
  * Author: hpstory (hpstory1024@163.com)
  */
 
-using hello_algo.utils;
-using NUnit.Framework;
-
 namespace hello_algo.chapter_graph;
 
 public class graph_dfs {

codes/csharp/chapter_hashing/array_hash_map.cs

@@ -4,8 +4,6 @@
  * Author: haptear (haptear@hotmail.com)
  */
 
-using NUnit.Framework;
-
 namespace hello_algo.chapter_hashing;
 
 /* 键值对 int->string */

codes/csharp/chapter_hashing/hash_map.cs

@@ -5,9 +5,6 @@
  * Author: haptear (haptear@hotmail.com)
  */
 
-using hello_algo.utils;
-using NUnit.Framework;
-
 namespace hello_algo.chapter_hashing;
 
 public class hash_map {

codes/csharp/chapter_heap/heap.cs

@@ -4,9 +4,6 @@
  * Author: zjkung1123 (zjkung1123@gmail.com)
  */
 
-using hello_algo.utils;
-using NUnit.Framework;
-
 namespace hello_algo.chapter_heap;
 
 public class heap {

codes/csharp/chapter_heap/my_heap.cs

@@ -4,9 +4,6 @@
  * Author: zjkung1123 (zjkung1123@gmail.com)
  */
 
-using hello_algo.utils;
-using NUnit.Framework;
-
 namespace hello_algo.chapter_heap;
 
 /* 大顶堆 */

codes/csharp/chapter_searching/hashing_search.cs

@@ -4,9 +4,6 @@
  * Author: haptear (haptear@hotmail.com)
  */
 
-using hello_algo.utils;
-using NUnit.Framework;
-
 namespace hello_algo.chapter_searching;
 
 public class hashing_search {

codes/csharp/chapter_searching/leetcode_two_sum.cs

@@ -4,8 +4,6 @@
  * Author: haptear (haptear@hotmail.com)
  */
 
-using NUnit.Framework;
-
 namespace hello_algo.chapter_searching;
 
 public class leetcode_two_sum {

codes/csharp/chapter_searching/linear_search.cs

@@ -4,9 +4,6 @@
  * Author: haptear (haptear@hotmail.com)
  */
 
-using hello_algo.utils;
-using NUnit.Framework;
-
 namespace hello_algo.chapter_searching;
 
 public class linear_search {

codes/csharp/chapter_sorting/bubble_sort.cs

@@ -4,8 +4,6 @@
  * Author: haptear (haptear@hotmail.com)
  */
 
-using NUnit.Framework;
-
 namespace hello_algo.chapter_sorting;
 
 public class bubble_sort {

codes/csharp/chapter_sorting/bucket_sort.cs

@@ -4,8 +4,6 @@
  * Author: hpstory (hpstory1024@163.com)
  */
 
-using NUnit.Framework;
-
 namespace hello_algo.chapter_sorting;
 
 public class bucket_sort {

codes/csharp/chapter_sorting/counting_sort.cs

@@ -4,8 +4,6 @@
  * Author: hpstory (hpstory1024@163.com)
  */
 
-using NUnit.Framework;
-
 namespace hello_algo.chapter_sorting;
 
 public class counting_sort {

codes/csharp/chapter_sorting/insertion_sort.cs

@@ -4,8 +4,6 @@
  * Author: haptear (haptear@hotmail.com)
  */
 
-using NUnit.Framework;
-
 namespace hello_algo.chapter_sorting;
 
 public class insertion_sort {

codes/csharp/chapter_sorting/merge_sort.cs

@@ -4,8 +4,6 @@
  * Author: haptear (haptear@hotmail.com)
  */
 
-using NUnit.Framework;
-
 namespace hello_algo.chapter_sorting;
 
 public class merge_sort {

codes/csharp/chapter_sorting/quick_sort.cs

@@ -4,8 +4,6 @@
  * Author: haptear (haptear@hotmail.com)
  */
 
-using NUnit.Framework;
-
 namespace hello_algo.chapter_sorting;
 
 class QuickSort {

codes/csharp/chapter_sorting/radix_sort.cs

@@ -4,8 +4,6 @@
  * Author: hpstory (hpstory1024@163.com)
  */
 
-using NUnit.Framework;
-
 namespace hello_algo.chapter_sorting;
 
 public class radix_sort {

codes/csharp/chapter_stack_and_queue/array_deque.cs

@@ -4,151 +4,149 @@
  * Author: hpstory (hpstory1024@163.com)
  */
 
-using NUnit.Framework;
+namespace hello_algo.chapter_stack_and_queue;
 
-namespace hello_algo.chapter_stack_and_queue {
+/* 基于环形数组实现的双向队列 */
-    /* 基于环形数组实现的双向队列 */
+public class ArrayDeque {
-    public class ArrayDeque {
+    private readonly int[] nums;  // 用于存储双向队列元素的数组
-        private readonly int[] nums;  // 用于存储双向队列元素的数组
+    private int front;   // 队首指针，指向队首元素
-        private int front;   // 队首指针，指向队首元素
+    private int queSize; // 双向队列长度
-        private int queSize; // 双向队列长度
 
-        /* 构造方法 */
+    /* 构造方法 */
-        public ArrayDeque(int capacity) {
+    public ArrayDeque(int capacity) {
-            this.nums = new int[capacity];
+        this.nums = new int[capacity];
-            front = queSize = 0;
+        front = queSize = 0;
-        }
-
-        /* 获取双向队列的容量 */
-        public int capacity() {
-            return nums.Length;
-        }
-
-        /* 获取双向队列的长度 */
-        public int size() {
-            return queSize;
-        }
-
-        /* 判断双向队列是否为空 */
-        public bool isEmpty() {
-            return queSize == 0;
-        }
-
-        /* 计算环形数组索引 */
-        private int index(int i) {
-            // 通过取余操作实现数组首尾相连
-            // 当 i 越过数组尾部后，回到头部
-            // 当 i 越过数组头部后，回到尾部
-            return (i + capacity()) % capacity();
-        }
-
-        /* 队首入队 */
-        public void pushFirst(int num) {
-            if (queSize == capacity()) {
-                Console.WriteLine("双向队列已满");
-                return;
-            }
-            // 队首指针向左移动一位
-            // 通过取余操作，实现 front 越过数组头部后回到尾部
-            front = index(front - 1);
-            // 将 num 添加至队首
-            nums[front] = num;
-            queSize++;
-        }
-
-        /* 队尾入队 */
-        public void pushLast(int num) {
-            if (queSize == capacity()) {
-                Console.WriteLine("双向队列已满");
-                return;
-            }
-            // 计算尾指针，指向队尾索引 + 1
-            int rear = index(front + queSize);
-            // 将 num 添加至队尾
-            nums[rear] = num;
-            queSize++;
-        }
-
-        /* 队首出队 */
-        public int popFirst() {
-            int num = peekFirst();
-            // 队首指针向后移动一位
-            front = index(front + 1);
-            queSize--;
-            return num;
-        }
-
-        /* 队尾出队 */
-        public int popLast() {
-            int num = peekLast();
-            queSize--;
-            return num;
-        }
-
-        /* 访问队首元素 */
-        public int peekFirst() {
-            if (isEmpty()) {
-                throw new InvalidOperationException();
-            }
-            return nums[front];
-        }
-
-        /* 访问队尾元素 */
-        public int peekLast() {
-            if (isEmpty()) {
-                throw new InvalidOperationException();
-            }
-            // 计算尾元素索引
-            int last = index(front + queSize - 1);
-            return nums[last];
-        }
-
-        /* 返回数组用于打印 */
-        public int[] toArray() {
-            // 仅转换有效长度范围内的列表元素
-            int[] res = new int[queSize];
-            for (int i = 0, j = front; i < queSize; i++, j++) {
-                res[i] = nums[index(j)];
-            }
-            return res;
-        }
     }
 
-    public class array_deque {
+    /* 获取双向队列的容量 */
-        [Test]
+    public int capacity() {
-        public void Test() {
+        return nums.Length;
-            /* 初始化双向队列 */
+    }
-            ArrayDeque deque = new ArrayDeque(10);
-            deque.pushLast(3);
-            deque.pushLast(2);
-            deque.pushLast(5);
-            Console.WriteLine("双向队列 deque = " + string.Join(" ", deque.toArray()));
 
-            /* 访问元素 */
+    /* 获取双向队列的长度 */
-            int peekFirst = deque.peekFirst();
+    public int size() {
-            Console.WriteLine("队首元素 peekFirst = " + peekFirst);
+        return queSize;
-            int peekLast = deque.peekLast();
+    }
-            Console.WriteLine("队尾元素 peekLast = " + peekLast);
 
-            /* 元素入队 */
+    /* 判断双向队列是否为空 */
-            deque.pushLast(4);
+    public bool isEmpty() {
-            Console.WriteLine("元素 4 队尾入队后 deque = " + string.Join(" ", deque.toArray()));
+        return queSize == 0;
-            deque.pushFirst(1);
+    }
-            Console.WriteLine("元素 1 队首入队后 deque = " + string.Join(" ", deque.toArray()));
 
-            /* 元素出队 */
+    /* 计算环形数组索引 */
-            int popLast = deque.popLast();
+    private int index(int i) {
-            Console.WriteLine("队尾出队元素 = " + popLast + "，队尾出队后 deque = " + string.Join(" ", deque.toArray()));
+        // 通过取余操作实现数组首尾相连
-            int popFirst = deque.popFirst();
+        // 当 i 越过数组尾部后，回到头部
-            Console.WriteLine("队首出队元素 = " + popFirst + "，队首出队后 deque = " + string.Join(" ", deque.toArray()));
+        // 当 i 越过数组头部后，回到尾部
+        return (i + capacity()) % capacity();
+    }
 
-            /* 获取双向队列的长度 */
+    /* 队首入队 */
-            int size = deque.size();
+    public void pushFirst(int num) {
-            Console.WriteLine("双向队列长度 size = " + size);
+        if (queSize == capacity()) {
-
+            Console.WriteLine("双向队列已满");
-            /* 判断双向队列是否为空 */
+            return;
-            bool isEmpty = deque.isEmpty();
-            Console.WriteLine("双向队列是否为空 = " + isEmpty);
         }
+        // 队首指针向左移动一位
+        // 通过取余操作，实现 front 越过数组头部后回到尾部
+        front = index(front - 1);
+        // 将 num 添加至队首
+        nums[front] = num;
+        queSize++;
+    }
+
+    /* 队尾入队 */
+    public void pushLast(int num) {
+        if (queSize == capacity()) {
+            Console.WriteLine("双向队列已满");
+            return;
+        }
+        // 计算尾指针，指向队尾索引 + 1
+        int rear = index(front + queSize);
+        // 将 num 添加至队尾
+        nums[rear] = num;
+        queSize++;
+    }
+
+    /* 队首出队 */
+    public int popFirst() {
+        int num = peekFirst();
+        // 队首指针向后移动一位
+        front = index(front + 1);
+        queSize--;
+        return num;
+    }
+
+    /* 队尾出队 */
+    public int popLast() {
+        int num = peekLast();
+        queSize--;
+        return num;
+    }
+
+    /* 访问队首元素 */
+    public int peekFirst() {
+        if (isEmpty()) {
+            throw new InvalidOperationException();
+        }
+        return nums[front];
+    }
+
+    /* 访问队尾元素 */
+    public int peekLast() {
+        if (isEmpty()) {
+            throw new InvalidOperationException();
+        }
+        // 计算尾元素索引
+        int last = index(front + queSize - 1);
+        return nums[last];
+    }
+
+    /* 返回数组用于打印 */
+    public int[] toArray() {
+        // 仅转换有效长度范围内的列表元素
+        int[] res = new int[queSize];
+        for (int i = 0, j = front; i < queSize; i++, j++) {
+            res[i] = nums[index(j)];
+        }
+        return res;
+    }
+}
+
+public class array_deque {
+    [Test]
+    public void Test() {
+        /* 初始化双向队列 */
+        ArrayDeque deque = new ArrayDeque(10);
+        deque.pushLast(3);
+        deque.pushLast(2);
+        deque.pushLast(5);
+        Console.WriteLine("双向队列 deque = " + string.Join(" ", deque.toArray()));
+
+        /* 访问元素 */
+        int peekFirst = deque.peekFirst();
+        Console.WriteLine("队首元素 peekFirst = " + peekFirst);
+        int peekLast = deque.peekLast();
+        Console.WriteLine("队尾元素 peekLast = " + peekLast);
+
+        /* 元素入队 */
+        deque.pushLast(4);
+        Console.WriteLine("元素 4 队尾入队后 deque = " + string.Join(" ", deque.toArray()));
+        deque.pushFirst(1);
+        Console.WriteLine("元素 1 队首入队后 deque = " + string.Join(" ", deque.toArray()));
+
+        /* 元素出队 */
+        int popLast = deque.popLast();
+        Console.WriteLine("队尾出队元素 = " + popLast + "，队尾出队后 deque = " + string.Join(" ", deque.toArray()));
+        int popFirst = deque.popFirst();
+        Console.WriteLine("队首出队元素 = " + popFirst + "，队首出队后 deque = " + string.Join(" ", deque.toArray()));
+
+        /* 获取双向队列的长度 */
+        int size = deque.size();
+        Console.WriteLine("双向队列长度 size = " + size);
+
+        /* 判断双向队列是否为空 */
+        bool isEmpty = deque.isEmpty();
+        Console.WriteLine("双向队列是否为空 = " + isEmpty);
     }
 }

codes/csharp/chapter_stack_and_queue/array_queue.cs

@@ -4,8 +4,6 @@
  * Author: haptear (haptear@hotmail.com)
  */
 
-using NUnit.Framework;
-
 namespace hello_algo.chapter_stack_and_queue;
 
 /* 基于环形数组实现的队列 */

codes/csharp/chapter_stack_and_queue/array_stack.cs

@@ -4,8 +4,6 @@
  * Author: haptear (haptear@hotmail.com)
  */
 
-using NUnit.Framework;
-
 namespace hello_algo.chapter_stack_and_queue;
 
 /* 基于数组实现的栈 */

codes/csharp/chapter_stack_and_queue/deque.cs

@@ -4,8 +4,6 @@
  * Author: moonache (microin1301@outlook.com)
  */
 
-using NUnit.Framework;
-
 namespace hello_algo.chapter_stack_and_queue;
 
 public class deque {

codes/csharp/chapter_stack_and_queue/linkedlist_deque.cs

@@ -4,183 +4,181 @@
  * Author: hpstory (hpstory1024@163.com)
  */
 
-using NUnit.Framework;
+namespace hello_algo.chapter_stack_and_queue;
 
-namespace hello_algo.chapter_stack_and_queue {
+/* 双向链表节点 */
-    /* 双向链表节点 */
+public class ListNode {
-    public class ListNode {
+    public int val;       // 节点值
-        public int val;       // 节点值
+    public ListNode? next; // 后继节点引用（指针）
-        public ListNode? next; // 后继节点引用（指针）
+    public ListNode? prev; // 前驱节点引用（指针）
-        public ListNode? prev; // 前驱节点引用（指针）
 
-        public ListNode(int val) {
+    public ListNode(int val) {
-            this.val = val;
+        this.val = val;
-            prev = null;
+        prev = null;
-            next = null;
+        next = null;
-        }
+    }
-    }
+}
-
+
-    /* 基于双向链表实现的双向队列 */
+/* 基于双向链表实现的双向队列 */
-    public class LinkedListDeque {
+public class LinkedListDeque {
-        private ListNode? front, rear; // 头节点 front, 尾节点 rear
+    private ListNode? front, rear; // 头节点 front, 尾节点 rear
-        private int queSize = 0;      // 双向队列的长度
+    private int queSize = 0;      // 双向队列的长度
-
+
-        public LinkedListDeque() {
+    public LinkedListDeque() {
-            front = null;
+        front = null;
-            rear = null;
+        rear = null;
-        }
+    }
-
+
-        /* 获取双向队列的长度 */
+    /* 获取双向队列的长度 */
-        public int size() {
+    public int size() {
-            return queSize;
+        return queSize;
-        }
+    }
-
+
-        /* 判断双向队列是否为空 */
+    /* 判断双向队列是否为空 */
-        public bool isEmpty() {
+    public bool isEmpty() {
-            return size() == 0;
+        return size() == 0;
-        }
+    }
-
+
-        /* 入队操作 */
+    /* 入队操作 */
-        private void push(int num, bool isFront) {
+    private void push(int num, bool isFront) {
-            ListNode node = new ListNode(num);
+        ListNode node = new ListNode(num);
-            // 若链表为空，则令 front, rear 都指向 node
+        // 若链表为空，则令 front, rear 都指向 node
-            if (isEmpty()) {
+        if (isEmpty()) {
-                front = node;
+            front = node;
-                rear = node;
+            rear = node;
-            }
+        }
-            // 队首入队操作
+        // 队首入队操作
-            else if (isFront) {
+        else if (isFront) {
-                // 将 node 添加至链表头部
+            // 将 node 添加至链表头部
-                front.prev = node;
+            front.prev = node;
-                node.next = front;
+            node.next = front;
-                front = node; // 更新头节点                           
+            front = node; // 更新头节点                           
-            }
+        }
-            // 队尾入队操作
+        // 队尾入队操作
-            else {
+        else {
-                // 将 node 添加至链表尾部
+            // 将 node 添加至链表尾部
-                rear.next = node;
+            rear.next = node;
-                node.prev = rear;
+            node.prev = rear;
-                rear = node;  // 更新尾节点
+            rear = node;  // 更新尾节点
-            }
+        }
-
+
-            queSize++; // 更新队列长度
+        queSize++; // 更新队列长度
-        }
+    }
-
+
-        /* 队首入队 */
+    /* 队首入队 */
-        public void pushFirst(int num) {
+    public void pushFirst(int num) {
-            push(num, true);
+        push(num, true);
-        }
+    }
-
+
-        /* 队尾入队 */
+    /* 队尾入队 */
-        public void pushLast(int num) {
+    public void pushLast(int num) {
-            push(num, false);
+        push(num, false);
-        }
+    }
-
+
-        /* 出队操作 */
+    /* 出队操作 */
-        private int? pop(bool isFront) {
+    private int? pop(bool isFront) {
-            // 若队列为空，直接返回 null
+        // 若队列为空，直接返回 null
-            if (isEmpty()) {
+        if (isEmpty()) {
-                return null;
+            return null;
-            }
+        }
-
+
-            int val;
+        int val;
-            // 队首出队操作
+        // 队首出队操作
-            if (isFront) {
+        if (isFront) {
-                val = front.val; // 暂存头节点值
+            val = front.val; // 暂存头节点值
-                                 // 删除头节点
+                             // 删除头节点
-                ListNode fNext = front.next;
+            ListNode fNext = front.next;
-                if (fNext != null) {
+            if (fNext != null) {
-                    fNext.prev = null;
+                fNext.prev = null;
-                    front.next = null;
+                front.next = null;
-                }
+            }
-
+
-                front = fNext;   // 更新头节点
+            front = fNext;   // 更新头节点
-            }
+        }
-            // 队尾出队操作
+        // 队尾出队操作
-            else {
+        else {
-                val = rear.val;  // 暂存尾节点值
+            val = rear.val;  // 暂存尾节点值
-                                 // 删除尾节点
+                             // 删除尾节点
-                ListNode rPrev = rear.prev;
+            ListNode rPrev = rear.prev;
-                if (rPrev != null) {
+            if (rPrev != null) {
-                    rPrev.next = null;
+                rPrev.next = null;
-                    rear.prev = null;
+                rear.prev = null;
-                }
+            }
-
+
-                rear = rPrev;    // 更新尾节点
+            rear = rPrev;    // 更新尾节点
-            }
+        }
-
+
-            queSize--; // 更新队列长度
+        queSize--; // 更新队列长度
-            return val;
+        return val;
-        }
+    }
-
+
-        /* 队首出队 */
+    /* 队首出队 */
-        public int? popFirst() {
+    public int? popFirst() {
-            return pop(true);
+        return pop(true);
-        }
+    }
-
+
-        /* 队尾出队 */
+    /* 队尾出队 */
-        public int? popLast() {
+    public int? popLast() {
-            return pop(false);
+        return pop(false);
-        }
+    }
-
+
-        /* 访问队首元素 */
+    /* 访问队首元素 */
-        public int? peekFirst() {
+    public int? peekFirst() {
-            return isEmpty() ? null : front.val;
+        return isEmpty() ? null : front.val;
-        }
+    }
-
+
-        /* 访问队尾元素 */
+    /* 访问队尾元素 */
-        public int? peekLast() {
+    public int? peekLast() {
-            return isEmpty() ? null : rear.val;
+        return isEmpty() ? null : rear.val;
-        }
+    }
-
+
-        /* 返回数组用于打印 */
+    /* 返回数组用于打印 */
-        public int[] toArray() {
+    public int[] toArray() {
-            ListNode node = front;
+        ListNode node = front;
-            int[] res = new int[size()];
+        int[] res = new int[size()];
-            for (int i = 0; i < res.Length; i++) {
+        for (int i = 0; i < res.Length; i++) {
-                res[i] = node.val;
+            res[i] = node.val;
-                node = node.next;
+            node = node.next;
-            }
+        }
-
+
-            return res;
+        return res;
-        }
+    }
-    }
+}
-
+
-    public class linkedlist_deque {
+public class linkedlist_deque {
-        [Test]
+    [Test]
-        public void Test() {
+    public void Test() {
-            /* 初始化双向队列 */
+        /* 初始化双向队列 */
-            LinkedListDeque deque = new LinkedListDeque();
+        LinkedListDeque deque = new LinkedListDeque();
-            deque.pushLast(3);
+        deque.pushLast(3);
-            deque.pushLast(2);
+        deque.pushLast(2);
-            deque.pushLast(5);
+        deque.pushLast(5);
-            Console.WriteLine("双向队列 deque = " + string.Join(" ", deque.toArray()));
+        Console.WriteLine("双向队列 deque = " + string.Join(" ", deque.toArray()));
-
+
-            /* 访问元素 */
+        /* 访问元素 */
-            int? peekFirst = deque.peekFirst();
+        int? peekFirst = deque.peekFirst();
-            Console.WriteLine("队首元素 peekFirst = " + peekFirst);
+        Console.WriteLine("队首元素 peekFirst = " + peekFirst);
-            int? peekLast = deque.peekLast();
+        int? peekLast = deque.peekLast();
-            Console.WriteLine("队尾元素 peekLast = " + peekLast);
+        Console.WriteLine("队尾元素 peekLast = " + peekLast);
-
+
-            /* 元素入队 */
+        /* 元素入队 */
-            deque.pushLast(4);
+        deque.pushLast(4);
-            Console.WriteLine("元素 4 队尾入队后 deque = " + string.Join(" ", deque.toArray()));
+        Console.WriteLine("元素 4 队尾入队后 deque = " + string.Join(" ", deque.toArray()));
-            deque.pushFirst(1);
+        deque.pushFirst(1);
-            Console.WriteLine("元素 1 队首入队后 deque = " + string.Join(" ", deque.toArray()));
+        Console.WriteLine("元素 1 队首入队后 deque = " + string.Join(" ", deque.toArray()));
-
+
-            /* 元素出队 */
+        /* 元素出队 */
-            int? popLast = deque.popLast();
+        int? popLast = deque.popLast();
-            Console.WriteLine("队尾出队元素 = " + popLast + "，队尾出队后 deque = " + string.Join(" ", deque.toArray()));
+        Console.WriteLine("队尾出队元素 = " + popLast + "，队尾出队后 deque = " + string.Join(" ", deque.toArray()));
-            int? popFirst = deque.popFirst();
+        int? popFirst = deque.popFirst();
-            Console.WriteLine("队首出队元素 = " + popFirst + "，队首出队后 deque = " + string.Join(" ", deque.toArray()));
+        Console.WriteLine("队首出队元素 = " + popFirst + "，队首出队后 deque = " + string.Join(" ", deque.toArray()));
-
+
-            /* 获取双向队列的长度 */
+        /* 获取双向队列的长度 */
-            int size = deque.size();
+        int size = deque.size();
-            Console.WriteLine("双向队列长度 size = " + size);
+        Console.WriteLine("双向队列长度 size = " + size);
-
+
-            /* 判断双向队列是否为空 */
+        /* 判断双向队列是否为空 */
-            bool isEmpty = deque.isEmpty();
+        bool isEmpty = deque.isEmpty();
-            Console.WriteLine("双向队列是否为空 = " + isEmpty);
+        Console.WriteLine("双向队列是否为空 = " + isEmpty);
-        }
     }
 }

codes/csharp/chapter_stack_and_queue/linkedlist_queue.cs

@@ -4,9 +4,6 @@
  * Author: haptear (haptear@hotmail.com)
  */
 
-using hello_algo.utils;
-using NUnit.Framework;
-
 namespace hello_algo.chapter_stack_and_queue;
 
 /* 基于链表实现的队列 */

codes/csharp/chapter_stack_and_queue/linkedlist_stack.cs

@@ -4,9 +4,6 @@
  * Author: haptear (haptear@hotmail.com)
  */
 
-using hello_algo.utils;
-using NUnit.Framework;
-
 namespace hello_algo.chapter_stack_and_queue;
 
 /* 基于链表实现的栈 */

codes/csharp/chapter_stack_and_queue/queue.cs

@@ -4,8 +4,6 @@
  * Author: haptear (haptear@hotmail.com)
  */
 
-using NUnit.Framework;
-
 namespace hello_algo.chapter_stack_and_queue;
 
 public class queue {

codes/csharp/chapter_stack_and_queue/stack.cs

@@ -4,8 +4,6 @@
  * Author: haptear (haptear@hotmail.com)
  */
 
-using NUnit.Framework;
-
 namespace hello_algo.chapter_stack_and_queue;
 
 public class stack {

codes/csharp/chapter_tree/avl_tree.cs

@@ -4,9 +4,6 @@
  * Author: haptear (haptear@hotmail.com)
  */
 
-using hello_algo.utils;
-using NUnit.Framework;
-
 namespace hello_algo.chapter_tree;
 
 /* AVL 树 */

codes/csharp/chapter_tree/binary_search_tree.cs

@@ -4,9 +4,6 @@
  * Author: haptear (haptear@hotmail.com)
  */
 
-using hello_algo.utils;
-using NUnit.Framework;
-
 namespace hello_algo.chapter_tree;
 
 class BinarySearchTree {

codes/csharp/chapter_tree/binary_tree.cs

@@ -4,9 +4,6 @@
  * Author: haptear (haptear@hotmail.com)
  */
 
-using hello_algo.utils;
-using NUnit.Framework;
-
 namespace hello_algo.chapter_tree;
 
 public class binary_tree {

codes/csharp/chapter_tree/binary_tree_bfs.cs

@@ -4,9 +4,6 @@
  * Author: haptear (haptear@hotmail.com)
  */
 
-using hello_algo.utils;
-using NUnit.Framework;
-
 namespace hello_algo.chapter_tree;
 
 public class binary_tree_bfs {

codes/csharp/chapter_tree/binary_tree_dfs.cs

@@ -4,9 +4,6 @@
  * Author: haptear (haptear@hotmail.com)
  */
 
-using hello_algo.utils;
-using NUnit.Framework;
-
 namespace hello_algo.chapter_tree;
 
 public class binary_tree_dfs {