diff --git a/codes/rust/Cargo.toml b/codes/rust/Cargo.toml index 86b27111..ab910f9a 100644 --- a/codes/rust/Cargo.toml +++ b/codes/rust/Cargo.toml @@ -334,5 +334,20 @@ path = "chapter_backtracking/preorder_traversal_iii_compact.rs" name = "preorder_traversal_iii_template" path = "chapter_backtracking/preorder_traversal_iii_template.rs" +# Run Command: cargo run --bin binary_search_recur +[[bin]] +name = "binary_search_recur" +path = "chapter_divide_and_conquer/binary_search_recur.rs" + +# Run Command: cargo run --bin hanota +[[bin]] +name = "hanota" +path = "chapter_divide_and_conquer/hanota.rs" + +# Run Command: cargo run --bin build_tree +[[bin]] +name = "build_tree" +path = "chapter_divide_and_conquer/build_tree.rs" + [dependencies] rand = "0.8.5" \ No newline at end of file diff --git a/codes/rust/chapter_divide_and_conquer/binary_search_recur.rs b/codes/rust/chapter_divide_and_conquer/binary_search_recur.rs new file mode 100644 index 00000000..01e75080 --- /dev/null +++ b/codes/rust/chapter_divide_and_conquer/binary_search_recur.rs @@ -0,0 +1,39 @@ +/* + * File: binary_search_recur.rs + * Created Time: 2023-07-15 + * Author: sjinzh (sjinzh@gmail.com) + */ + +/* 二分查找:问题 f(i, j) */ +fn dfs(nums: &[i32], target: i32, i: i32, j: i32) -> i32 { + // 若区间为空,代表无目标元素,则返回 -1 + if i > j { return -1; } + let m: i32 = (i + j) / 2; + if nums[m as usize] < target { + // 递归子问题 f(m+1, j) + return dfs(nums, target, m + 1, j); + } else if nums[m as usize] > target { + // 递归子问题 f(i, m-1) + return dfs(nums, target, i, m - 1); + } else { + // 找到目标元素,返回其索引 + return m; + } +} + +/* 二分查找 */ +fn binary_search(nums: &[i32], target: i32) -> i32 { + let n = nums.len() as i32; + // 求解问题 f(0, n-1) + dfs(nums, target, 0, n - 1) +} + +/* Driver Code */ +pub fn main() { + let target = 6; + let nums = [ 1, 3, 6, 8, 12, 15, 23, 26, 31, 35 ]; + + // 二分查找(双闭区间) + let index = binary_search(&nums, target); + println!("目标元素 6 的索引 = {index}"); +} diff --git a/codes/rust/chapter_divide_and_conquer/build_tree.rs b/codes/rust/chapter_divide_and_conquer/build_tree.rs new file mode 100644 index 00000000..b31a9138 --- /dev/null +++ b/codes/rust/chapter_divide_and_conquer/build_tree.rs @@ -0,0 +1,50 @@ +/* + * File: build_tree.rs + * Created Time: 2023-07-15 + * Author: sjinzh (sjinzh@gmail.com) + */ + + use std::{cell::RefCell, rc::Rc}; + use std::collections::HashMap; + include!("../include/include.rs"); + use tree_node::TreeNode; + +/* 构建二叉树:分治 */ +fn dfs(preorder: &[i32], inorder: &[i32], hmap: &HashMap, i: i32, l: i32, r: i32) -> Option>> { + // 子树区间为空时终止 + if r - l < 0 { return None; } + // 初始化根节点 + let root = TreeNode::new(preorder[i as usize]); + // 查询 m ,从而划分左右子树 + let m = hmap.get(&preorder[i as usize]).unwrap(); + // 子问题:构建左子树 + root.borrow_mut().left = dfs(preorder, inorder, hmap, i + 1, l, m - 1); + // 子问题:构建右子树 + root.borrow_mut().right = dfs(preorder, inorder, hmap, i + 1 + m - l, m + 1, r); + // 返回根节点 + Some(root) +} + +/* 构建二叉树 */ + fn build_tree(preorder: &[i32], inorder: &[i32]) -> Option>> { + // 初始化哈希表,存储 inorder 元素到索引的映射 + let mut hmap: HashMap = HashMap::new(); + for i in 0..inorder.len() { + hmap.insert(inorder[i], i as i32); + } + let root = dfs(preorder, inorder, &hmap, 0, 0, inorder.len() as i32 - 1); + root +} + + /* Driver Code */ + fn main() { + let preorder = [ 3, 9, 2, 1, 7 ]; + let inorder = [ 9, 3, 1, 2, 7 ]; + println!("中序遍历 = {:?}", preorder); + println!("前序遍历 = {:?}", inorder); + + let root = build_tree(&preorder, &inorder); + println!("构建的二叉树为:"); + print_util::print_tree(root.as_ref().unwrap()); + } + \ No newline at end of file diff --git a/codes/rust/chapter_divide_and_conquer/hanota.rs b/codes/rust/chapter_divide_and_conquer/hanota.rs new file mode 100644 index 00000000..ab4ef70e --- /dev/null +++ b/codes/rust/chapter_divide_and_conquer/hanota.rs @@ -0,0 +1,53 @@ +/* + * File: hanota.rs + * Created Time: 2023-07-15 + * Author: sjinzh (sjinzh@gmail.com) + */ + +/* 移动一个圆盘 */ +fn move_pan(src: &mut Vec, tar: &mut Vec) { + // 从 src 顶部拿出一个圆盘 + let pan = src.remove(src.len() - 1); + // 将圆盘放入 tar 顶部 + tar.push(pan); +} + +/* 求解汉诺塔:问题 f(i) */ +fn dfs(i: i32, src: &mut Vec, buf: &mut Vec, tar: &mut Vec) { + // 若 src 只剩下一个圆盘,则直接将其移到 tar + if i == 1 { + move_pan(src, tar); + return; + } + // 子问题 f(i-1) :将 src 顶部 i-1 个圆盘借助 tar 移到 buf + dfs(i - 1, src, tar, buf); + // 子问题 f(1) :将 src 剩余一个圆盘移到 tar + move_pan(src, tar); + // 子问题 f(i-1) :将 buf 顶部 i-1 个圆盘借助 src 移到 tar + dfs(i - 1, buf, src, tar); +} + +/* 求解汉诺塔 */ +fn hanota(A: &mut Vec, B: &mut Vec, C: &mut Vec) { + let n = A.len() as i32; + // 将 A 顶部 n 个圆盘借助 B 移到 C + dfs(n, A, B, C); +} + +/* Driver Code */ +pub fn main() { + let mut A = vec![5, 4, 3, 2, 1]; + let mut B = Vec::new(); + let mut C = Vec::new(); + println!("初始状态下:"); + println!("A = {:?}", A); + println!("B = {:?}", B); + println!("C = {:?}", C); + + hanota(&mut A, &mut B, &mut C); + + println!("圆盘移动完成后:"); + println!("A = {:?}", A); + println!("B = {:?}", B); + println!("C = {:?}", C); +}