diff --git a/problems/0104.二叉树的最大深度.md b/problems/0104.二叉树的最大深度.md index f4c6cfc8..1f55f197 100644 --- a/problems/0104.二叉树的最大深度.md +++ b/problems/0104.二叉树的最大深度.md @@ -1033,6 +1033,9 @@ impl Solution { } ``` ### C# + +0104.二叉树的最大深度 + ```csharp // 递归法 public int MaxDepth(TreeNode root) { @@ -1088,7 +1091,76 @@ public int MaxDepth(TreeNode root) } ``` +559.n叉树的最大深度 +递归法 +```csharp + /* + 递归法 + */ + public class Solution { + public int MaxDepth(Node root) { + int res = 0; + /* 终止条件 */ + if(root == null){ + return 0; + } + + /* logic */ + // 遍历当前节点的子节点 + for (int i = 0; i < root.children.Count; i++) + { + res = Math.Max(res, MaxDepth(root.children[i])); + } + return res + 1; + } + } + // @lc code=end +``` + 迭代法（层序遍历） +```csharp + /* + 迭代法 + */ + public class Solution + { + public int MaxDepth(Node root) + { + Queue que = new Queue(); // 使用泛型队列存储节点 + + int res = 0; + + if(root != null){ + que.Enqueue(root); // 将根节点加入队列 + } + while (que.Count > 0) + { + int size = que.Count; // 获取当前层的节点数 + res++; // 深度加一 + + for (int i = 0; i < size; i++) + { + // 每一层的遍历 + + var curNode = que.Dequeue(); // 取出队列中的节点 + for (int j = 0; j < curNode.children.Count; j++) + { + if (curNode.children[j] != null) + { + que.Enqueue(curNode.children[j]); // 将子节点加入队列 + } + } + } + } + + return res; // 返回树的最大深度 + + } + } +``` + +

+ diff --git a/problems/0112.路径总和.md b/problems/0112.路径总和.md index 28134a7c..d45be3bd 100644 --- a/problems/0112.路径总和.md +++ b/problems/0112.路径总和.md @@ -1523,8 +1523,64 @@ public bool HasPathSum(TreeNode root, int targetSum) return HasPathSum(root.left, targetSum - root.val) || HasPathSum(root.right, targetSum - root.val); } ``` +0113.路径总和： +```csharp +/* + * @lc app=leetcode id=113 lang=csharp + * 0113.路径总和 II + * [113] Path Sum II + * 递归法 + */ +public class Solution { + private List> result = new List>(); + private List path = new List(); + // Main function to find paths with the given sum + public IList> PathSum(TreeNode root, int targetSum) { + result.Clear(); + path.Clear(); + if (root == null) return result.Select(list => list as IList).ToList(); + path.Add(root.val); // Add the root node to the path + traversal(root, targetSum - root.val); // Start the traversal + return result.Select(list => list as IList).ToList(); + } + + // Recursive function to traverse the tree and find paths + private void traversal(TreeNode node, int count) { + // If a leaf node is reached and the target sum is achieved + if (node.left == null && node.right == null && count == 0) { + result.Add(new List(path)); // Add a copy of the path to the result + return; + } + + // If a leaf node is reached and the target sum is not achieved, or if it's not a leaf node + if (node.left == null && node.right == null) return; + + // Traverse the left subtree + if (node.left != null) { + path.Add(node.left.val); + count -= node.left.val; + traversal(node.left, count); // Recursive call + count += node.left.val; // Backtrack + path.RemoveAt(path.Count - 1); // Backtrack + } + + // Traverse the right subtree + if (node.right != null) { + path.Add(node.right.val); + count -= node.right.val; + traversal(node.right, count); // Recursive call + count += node.right.val; // Backtrack + path.RemoveAt(path.Count - 1); // Backtrack + } + } +} + +// @lc code=end + +```

+ diff --git a/problems/0417.太平洋大西洋水流问题.md b/problems/0417.太平洋大西洋水流问题.md index 53ae14ed..8fe0f1b4 100644 --- a/problems/0417.太平洋大西洋水流问题.md +++ b/problems/0417.太平洋大西洋水流问题.md @@ -562,7 +562,213 @@ function pacificAtlantic(heights) { } ``` +### go +dfs: + +```go +var DIRECTIONS = [4][2]int{{-1, 0}, {1, 0}, {0, -1}, {0, 1}} + +func pacificAtlantic(heights [][]int) [][]int { + res := make([][]int, 0) + pacific := make([][]bool, len(heights)) + atlantic := make([][]bool, len(heights)) + for i := 0; i < len(heights); i++ { + pacific[i] = make([]bool, len(heights[0])) + atlantic[i] = make([]bool, len(heights[0])) + } + // 列 + for i := 0; i < len(heights); i++ { + dfs(heights, pacific, i, 0) + dfs(heights, atlantic, i, len(heights[0])-1) + } + // 行 + for j := 0; j < len(heights[0]); j++ { + dfs(heights, pacific, 0, j) + dfs(heights, atlantic, len(heights)-1, j) + } + + for i := 0; i < len(heights); i++ { + for j := 0; j < len(heights[0]); j++ { + if pacific[i][j] && atlantic[i][j] { + res = append(res, []int{i, j}) + } + } + } + + return res +} + +func dfs(heights [][]int, visited [][]bool, i, j int) { + visited[i][j] = true + for _, d := range DIRECTIONS { + x, y := i+d[0], j+d[1] + if x < 0 || x >= len(heights) || y < 0 || y >= len(heights[0]) || heights[i][j] > heights[x][y] || visited[x][y] { + continue + } + + dfs(heights, visited, x, y) + } +} +``` + +bfs: + +```go +var DIRECTIONS = [4][2]int{{-1, 0}, {1, 0}, {0, -1}, {0, 1}} + +func pacificAtlantic(heights [][]int) [][]int { + res := make([][]int, 0) + pacific := make([][]bool, len(heights)) + atlantic := make([][]bool, len(heights)) + for i := 0; i < len(heights); i++ { + pacific[i] = make([]bool, len(heights[0])) + atlantic[i] = make([]bool, len(heights[0])) + } + // 列 + for i := 0; i < len(heights); i++ { + bfs(heights, pacific, i, 0) + bfs(heights, atlantic, i, len(heights[0])-1) + } + // 行 + for j := 0; j < len(heights[0]); j++ { + bfs(heights, pacific, 0, j) + bfs(heights, atlantic, len(heights)-1, j) + } + + for i := 0; i < len(heights); i++ { + for j := 0; j < len(heights[0]); j++ { + if pacific[i][j] && atlantic[i][j] { + res = append(res, []int{i, j}) + } + } + } + + return res +} + +func bfs(heights [][]int, visited [][]bool, i, j int) { + queue := make([][]int, 0) + queue = append(queue, []int{i, j}) + visited[i][j] = true + for len(queue) > 0 { + cur := queue[0] + queue = queue[1:] + for _, d := range DIRECTIONS { + x, y := cur[0]+d[0], cur[1]+d[1] + if x < 0 || x >= len(heights) || y < 0 || y >= len(heights[0]) || heights[cur[0]][cur[1]] > heights[x][y] || visited[x][y] { + continue + } + queue = append(queue, []int{x, y}) + visited[x][y] = true + } + } +} +``` + +### Rust + +dfs: + +```rust +impl Solution { + const DIRECTIONS: [(isize, isize); 4] = [(0, 1), (0, -1), (1, 0), (-1, 0)]; + pub fn pacific_atlantic(heights: Vec>) -> Vec> { + let (m, n) = (heights.len(), heights[0].len()); + let mut res = vec![]; + let (mut pacific, mut atlantic) = (vec![vec![false; n]; m], vec![vec![false; n]; m]); + + // 列 + for i in 0..m { + Self::dfs(&heights, &mut pacific, i, 0); + Self::dfs(&heights, &mut atlantic, i, n - 1); + } + + for j in 0..n { + Self::dfs(&heights, &mut pacific, 0, j); + Self::dfs(&heights, &mut atlantic, m - 1, j); + } + + for i in 0..m { + for j in 0..n { + if pacific[i][j] && atlantic[i][j] { + res.push(vec![i as i32, j as i32]); + } + } + } + + res + } + + pub fn dfs(heights: &[Vec], visited: &mut [Vec], i: usize, j: usize) { + visited[i][j] = true; + for (dx, dy) in Self::DIRECTIONS { + let (x, y) = (i as isize + dx, j as isize + dy); + if x < 0 || x >= heights.len() as isize || y < 0 || y >= heights[0].len() as isize { + continue; + } + let (x, y) = (x as usize, y as usize); + if !visited[x][y] && heights[x][y] >= heights[i][j] { + Self::dfs(heights, visited, x, y); + } + } + } +} +``` + +bfs: + +```rust +use std::collections::VecDeque; + +impl Solution { + const DIRECTIONS: [(isize, isize); 4] = [(0, 1), (0, -1), (1, 0), (-1, 0)]; + pub fn pacific_atlantic(heights: Vec>) -> Vec> { + let (m, n) = (heights.len(), heights[0].len()); + let mut res = vec![]; + let (mut pacific, mut atlantic) = (vec![vec![false; n]; m], vec![vec![false; n]; m]); + + // 列 + for i in 0..m { + Self::bfs(&heights, &mut pacific, i, 0); + Self::bfs(&heights, &mut atlantic, i, n - 1); + } + + for j in 0..n { + Self::bfs(&heights, &mut pacific, 0, j); + Self::bfs(&heights, &mut atlantic, m - 1, j); + } + + for i in 0..m { + for j in 0..n { + if pacific[i][j] && atlantic[i][j] { + res.push(vec![i as i32, j as i32]); + } + } + } + + res + } + + pub fn bfs(heights: &[Vec], visited: &mut [Vec], i: usize, j: usize) { + let mut queue = VecDeque::from([(i, j)]); + visited[i][j] = true; + while let Some((i, j)) = queue.pop_front() { + for (dx, dy) in Self::DIRECTIONS { + let (x, y) = (i as isize + dx, j as isize + dy); + if x < 0 || x >= heights.len() as isize || y < 0 || y >= heights[0].len() as isize { + continue; + } + let (x, y) = (x as usize, y as usize); + if !visited[x][y] && heights[x][y] >= heights[i][j] { + queue.push_back((x, y)); + visited[x][y] = true; + } + } + } + } +} +```

diff --git a/problems/0513.找树左下角的值.md b/problems/0513.找树左下角的值.md index 3cdcc801..d897bba1 100644 --- a/problems/0513.找树左下角的值.md +++ b/problems/0513.找树左下角的值.md @@ -716,9 +716,55 @@ public void Traversal(TreeNode root, int depth) return; } ``` +```csharp +/* + * @lc app=leetcode id=513 lang=csharp + * 迭代法 + * [513] Find Bottom Left Tree Value + */ + +// @lc code=start +public class Solution +{ + public int FindBottomLeftValue(TreeNode root) + { + Queue que = new Queue(); + + if (root != null) + { + que.Enqueue(root); + } + + int ans = 0; + while (que.Count != 0) + { + + int size = que.Count; + for (var i = 0; i < size; i++) + { + var curNode = que.Peek(); + que.Dequeue(); + if(i == 0){ + ans = curNode.val; + } + if (curNode.left != null) + { + que.Enqueue(curNode.left); + } + if (curNode.right != null) + { + que.Enqueue(curNode.right); + } + } + + } + return ans; + } +} +// @lc code=end +```

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