diff --git "a/problems/0101.345円257円271円347円247円260円344円272円214円345円217円211円346円240円221円.md" "b/problems/0101.345円257円271円347円247円260円344円272円214円345円217円211円346円240円221円.md"
index 36b39740d0..1b777dd527 100644
--- "a/problems/0101.345円257円271円347円247円260円344円272円214円345円217円211円346円240円221円.md"
+++ "b/problems/0101.345円257円271円347円247円260円344円272円214円345円217円211円346円240円221円.md"
@@ -897,6 +897,53 @@ impl Solution {
 }
 }
 ```
+### C#
+```C#
+// 递归
+public bool IsSymmetric(TreeNode root)
+{
+ if (root == null) return true;
+ return Compare(root.left, root.right);
+}
+public bool Compare(TreeNode left, TreeNode right)
+{
+ if(left == null && right != null) return false;
+ else if(left != null && right == null ) return false;
+ else if(left == null && right == null) return true;
+ else if(left.val != right.val) return false;
+
+ var outside = Compare(left.left, right.right);
+ var inside = Compare(left.right, right.left);
+
+ return outside&&inside;
+}
+```
+``` C#
+// 迭代法
+public bool IsSymmetric(TreeNode root)
+{
+ if (root == null) return true;
+ var st = new Stack<div class="naked_tr">();
+ st.Push(root.left);
+ st.Push(root.right);
+ while (st.Count != 0)
+ {
+ var left = st.Pop();
+ var right = st.Pop();
+ if (left == null && right == null)
+ continue;
+
+ if ((left == null &#124;&#124; right == null &#124;&#124; (left.val != right.val)))
+ return false;
+
+ st.Push(left.left);
+ st.Push(right.right);
+ st.Push(left.right);
+ st.Push(right.left);
+ }
+ return true;
+}
+```
 
 <p>
 <a href="https://programmercarl.com/other/kstar.html">
diff --git "a/problems/0102.344円272円214円345円217円211円346円240円221円347円232円204円345円261円202円345円272円217円351円201円215円345円216円206円.md" "b/problems/0102.344円272円214円345円217円211円346円240円221円347円232円204円345円261円202円345円272円217円351円201円215円345円216円206円.md"
index 51d030e784..e977279c56 100644
--- "a/problems/0102.344円272円214円345円217円211円346円240円221円347円232円204円345円261円202円345円272円217円351円201円215円345円216円206円.md"
+++ "b/problems/0102.344円272円214円345円217円211円346円240円221円347円232円204円345円261円202円345円272円217円351円201円215円345円216円206円.md"
@@ -462,6 +462,32 @@ impl Solution {
 }
 }
 ```
+### C#
+```C#
+public IList<ilist<int>> LevelOrder(TreeNode root)
+{
+ var res = new List<ilist<int>>();
+ var que = new Queue<div class="naked_tr">();
+ if (root == null) return res;
+ que.Enqueue(root);
+ while (que.Count != 0)
+ {
+ var size = que.Count;
+ var vec = new List<int>();
+ for (int i = 0; i < size; i++) + { + var cur = que.Dequeue(); + vec.Add(cur.val); + if (cur.left != null) que.Enqueue(cur.left); + if (cur.right != null) que.Enqueue(cur.right); + } + res.Add(vec); + + + } + return res; +} +``` **此时我们就掌握了二叉树的层序遍历了,那么如下九道力扣上的题目,只需要修改模板的两三行代码(不能再多了),便可打倒!** @@ -798,6 +824,31 @@ impl Solution { } } ``` +### C# +```C# +public IList<ilist<int>> LevelOrderBottom(TreeNode root)
+{
+ var res = new List<ilist<int>>();
+ var que = new Queue<div class="naked_tr">();
+ if (root == null) return res;
+ que.Enqueue(root);
+ while (que.Count != 0)
+ {
+ var size = que.Count;
+ var vec = new List<int>();
+ for (int i = 0; i < size; i++) + { + var cur = que.Dequeue(); + vec.Add(cur.val); + if (cur.left != null) que.Enqueue(cur.left); + if (cur.right != null) que.Enqueue(cur.right); + } + res.Add(vec); + } + res.Reverse(); + return res; +} +``` ## 199.二叉树的右视图 diff --git "a/problems/0104.344円272円214円345円217円211円346円240円221円347円232円204円346円234円200円345円244円247円346円267円261円345円272円246円.md" "b/problems/0104.344円272円214円345円217円211円346円240円221円347円232円204円346円234円200円345円244円247円346円267円261円345円272円246円.md" index 0504437521..ab3ce52eff 100644 --- "a/problems/0104.344円272円214円345円217円211円346円240円221円347円232円204円346円234円200円345円244円247円346円267円261円345円272円246円.md" +++ "b/problems/0104.344円272円214円345円217円211円346円240円221円347円232円204円346円234円200円345円244円247円346円267円261円345円272円246円.md" @@ -1022,6 +1022,61 @@ impl Solution { max_depth } ``` +### C# +```C# +// 递归法 +public int MaxDepth(TreeNode root) { + if(root == null) return 0; + + int leftDepth = MaxDepth(root.left); + int rightDepth = MaxDepth(root.right); + + return 1 + Math.Max(leftDepth, rightDepth); +} +``` +```C# +// 前序遍历 +int result = 0; +public int MaxDepth(TreeNode root) +{ + if (root == null) return result; + GetDepth(root, 1); + return result; +} +public void GetDepth(TreeNode root, int depth) +{ + result = depth> result ? depth : result;
+ if (root.left == null && root.right == null) return;
+
+ if (root.left != null)
+ GetDepth(root.left, depth + 1);
+ if (root.right != null)
+ GetDepth(root.right, depth + 1);
+ return;
+}
+```
+```C#
+// 迭代法
+public int MaxDepth(TreeNode root)
+{
+ int depth = 0;
+ Queue<div class="naked_tr"> que = new();
+ if (root == null) return depth;
+ que.Enqueue(root);
+ while (que.Count != 0)
+ {
+ int size = que.Count;
+ depth++;
+ for (int i = 0; i < size; i++) + { + var node = que.Dequeue(); + if (node.left != null) que.Enqueue(node.left); + if (node.right != null) que.Enqueue(node.right); + } + } + return depth; +} +``` <p>
 <a href="https://programmercarl.com/other/kstar.html">
diff --git "a/problems/0226.347円277円273円350円275円254円344円272円214円345円217円211円346円240円221円.md" "b/problems/0226.347円277円273円350円275円254円344円272円214円345円217円211円346円240円221円.md"
index 1151778364..8691953a3e 100644
--- "a/problems/0226.347円277円273円350円275円254円344円272円214円345円217円211円346円240円221円.md"
+++ "b/problems/0226.347円277円273円350円275円254円344円272円214円345円217円211円346円240円221円.md"
@@ -1018,25 +1018,13 @@ public class Solution {
 ```csharp
 //迭代
 public class Solution {
- public TreeNode InvertTree(TreeNode root) {
- if (root == null) return null;
- Stack<div class="naked_tr"> stack=new Stack<div class="naked_tr">();
- stack.Push(root);
- while(stack.Count>0)
- {
- TreeNode node = stack.Pop(); 
- swap(node);
- if(node.right!=null) stack.Push(node.right); 
- if(node.left!=null) stack.Push(node.left); 
- }
- return root;
- }
-
- public void swap(TreeNode node) {
- TreeNode temp = node.left;
- node.left = node.right;
- node.right = temp;
- }
+public TreeNode InvertTree(TreeNode root) {
+ if(root == null) return root;
+ (root.left,root.right) = (root.right, root.left);
+ InvertTree(root.left);
+ InvertTree(root.right);
+ return root;
+}
 }
 ```
 
diff --git "a/problems/0344.345円217円215円350円275円254円345円255円227円347円254円246円344円270円262円.md" "b/problems/0344.345円217円215円350円275円254円345円255円227円347円254円246円344円270円262円.md"
index 8a4fed4574..44184c53bc 100644
--- "a/problems/0344.345円217円215円350円275円254円345円255円227円347円254円246円344円270円262円.md"
+++ "b/problems/0344.345円217円215円350円275円254円345円255円227円347円254円246円344円270円262円.md"
@@ -250,6 +250,20 @@ class Solution:
 s[:] = [s[i] for i in range(len(s) - 1, -1, -1)]
 
 ```
+
+(版本七) 使用reverse()
+
+```python
+class Solution:
+ def reverseString(self, s: List[str]) -> None:
+ """
+ Do not return anything, modify s in-place instead.
+ """
+ # 原地反转,无返回值
+ s.reverse()
+ 
+```
+
 ### Go:
 
 ```Go
diff --git "a/problems/0383.350円265円216円351円207円221円344円277円241円.md" "b/problems/0383.350円265円216円351円207円221円344円277円241円.md"
index 3de48ce3da..b800c2320d 100644
--- "a/problems/0383.350円265円216円351円207円221円344円277円241円.md"
+++ "b/problems/0383.350円265円216円351円207円221円344円277円241円.md"
@@ -214,6 +214,19 @@ class Solution:
 return all(ransomNote.count(c) <= magazine.count(c) for c in set(ransomNote)) ``` +(版本六)使用count(简单易懂) + +```python3 +class Solution: + def canConstruct(self, ransomNote: str, magazine: str) -> bool:
+ for char in ransomNote:
+ if char in magazine and ransomNote.count(char) <= magazine.count(char): + continue + else: + return False + return True +``` + ### Go: ```go diff --git "a/problems/344円272円214円345円217円211円346円240円221円347円232円204円347円273円237円344円270円200円350円277円255円344円273円243円346円263円225円.md" "b/problems/344円272円214円345円217円211円346円240円221円347円232円204円347円273円237円344円270円200円350円277円255円344円273円243円346円263円225円.md" index 8089af64ec..ad79424da8 100644 --- "a/problems/344円272円214円345円217円211円346円240円221円347円232円204円347円273円237円344円270円200円350円277円255円344円273円243円346円263円225円.md" +++ "b/problems/344円272円214円345円217円211円346円240円221円347円232円204円347円273円237円344円270円200円350円277円255円344円273円243円346円263円225円.md" @@ -741,6 +741,99 @@ impl Solution{ } } ``` +### C# +```C# +// 前序遍历 +public IList<int> PreorderTraversal(TreeNode root)
+{
+ var res = new List<int>();
+ var st = new Stack<div class="naked_tr">();
+ if (root == null) return res;
+ st.Push(root);
+ while (st.Count != 0)
+ {
+ var node = st.Peek();
+ if (node == null)
+ {
+ st.Pop();
+ node = st.Peek();
+ st.Pop();
+ res.Add(node.val);
+ }
+ else
+ {
+ st.Pop();
+ if (node.right != null) st.Push(node.right);
+ if (node.left != null) st.Push(node.left);
+ st.Push(node);
+ st.Push(null);
+ }
+ }
+ return res;
+}
+```
+```C#
+// 中序遍历
+public IList<int> InorderTraversal(TreeNode root)
+{
+ var res = new List<int>();
+ var st = new Stack<div class="naked_tr">();
+ if (root == null) return res;
+ st.Push(root);
+ while (st.Count != 0)
+ {
+ var node = st.Peek();
+ if (node == null)
+ {
+ st.Pop();
+ node = st.Peek();
+ st.Pop();
+ res.Add(node.val);
+ }
+ else
+ {
+ st.Pop();
+ if (node.right != null) st.Push(node.right);
+ st.Push(node);
+ st.Push(null);
+ if (node.left != null) st.Push(node.left);
+ }
+ }
+ return res;
+}
+```
+
+```C#
+// 后序遍历
+public IList<int> PostorderTraversal(TreeNode root)
+{
+ var res = new List<int>();
+ var st = new Stack<div class="naked_tr">();
+ if (root == null) return res;
+ st.Push(root);
+ while (st.Count != 0)
+ {
+ var node = st.Peek();
+ if (node == null)
+ {
+ st.Pop();
+ node = st.Peek();
+ st.Pop();
+ res.Add(node.val);
+ }
+ else
+ {
+ st.Pop();
+ if (node.left != null) st.Push(node.left);
+ if (node.right != null) st.Push(node.right);
+ st.Push(node);
+ st.Push(null);
+ }
+ }
+ res.Reverse(0, res.Count);
+ return res;
+}
+```
 
 <p>
 <a href="https://programmercarl.com/other/kstar.html">
diff --git "a/problems/344円272円214円345円217円211円346円240円221円347円232円204円350円277円255円344円273円243円351円201円215円345円216円206円.md" "b/problems/344円272円214円345円217円211円346円240円221円347円232円204円350円277円255円344円273円243円351円201円215円345円216円206円.md"
index 69007995f0..e39709b882 100644
--- "a/problems/344円272円214円345円217円211円346円240円221円347円232円204円350円277円255円344円273円243円351円201円215円345円216円206円.md"
+++ "b/problems/344円272円214円345円217円211円346円240円221円347円232円204円350円277円255円344円273円243円351円201円215円345円216円206円.md"
@@ -695,6 +695,67 @@ impl Solution {
 }
 }
 ```
+### C#
+```C#
+// 前序遍历
+public IList<int> PreorderTraversal(TreeNode root)
+{
+ var st = new Stack<div class="naked_tr">();
+ var res = new List<int>();
+ if (root == null) return res;
+ st.Push(root);
+ while (st.Count != 0)
+ {
+ var node = st.Pop();
+ res.Add(node.val);
+ if (node.right != null)
+ st.Push(node.right);
+ if (node.left != null)
+ st.Push(node.left);
+ }
+ return res;
+} 
+
+// 中序遍历
+public IList<int> InorderTraversal(TreeNode root)
+{
+ var st = new Stack<div class="naked_tr">();
+ var res = new List<int>();
+ var cur = root;
+ while (st.Count != 0 &#124;&#124; cur != null)
+ {
+ if (cur != null)
+ {
+ st.Push(cur);
+ cur = cur.left;
+ }
+ else
+ {
+ cur = st.Pop();
+ res.Add(cur.val);
+ cur = cur.right;
+ }
+ }
+ return res;
+}
+// 后序遍历
+public IList<int> PostorderTraversal(TreeNode root)
+{
+ var res = new List<int>();
+ var st = new Stack<div class="naked_tr">();
+ if (root == null) return res;
+ st.Push(root);
+ while (st.Count != 0)
+ {
+ var cur = st.Pop();
+ res.Add(cur.val);
+ if (cur.left != null) st.Push(cur.left);
+ if (cur.right != null) st.Push(cur.right);
+ }
+ res.Reverse(0, res.Count());
+ return res;
+}
+```
 
 <p>
 <a href="https://programmercarl.com/other/kstar.html">
diff --git "a/problems/344円272円214円345円217円211円346円240円221円347円232円204円351円200円222円345円275円222円351円201円215円345円216円206円.md" "b/problems/344円272円214円345円217円211円346円240円221円347円232円204円351円200円222円345円275円222円351円201円215円345円216円206円.md"
index 730b18ac6d..6dad6e56de 100644
--- "a/problems/344円272円214円345円217円211円346円240円221円347円232円204円351円200円222円345円275円222円351円201円215円345円216円206円.md"
+++ "b/problems/344円272円214円345円217円211円346円240円221円347円232円204円351円200円222円345円275円222円351円201円215円345円216円206円.md"
@@ -565,6 +565,60 @@ impl Solution {
 }
 ```
 
+### C#
+```C#
+// 前序遍历
+public IList<int> PreorderTraversal(TreeNode root)
+{
+ var res = new List<int>();
+ if (root == null) return res;
+ Traversal(root, res);
+ return res;
+
+}
+public void Traversal(TreeNode cur, IList<int> res)
+{
+ if (cur == null) return;
+ res.Add(cur.val);
+ Traversal(cur.left, res);
+ Traversal(cur.right, res);
+}
+```
+```C#
+// 中序遍历
+public IList<int> InorderTraversal(TreeNode root)
+{
+ var res = new List<int>();
+ if (root == null) return res;
+ Traversal(root, res);
+ return res;
+}
+public void Traversal(TreeNode cur, IList<int> res)
+{
+ if (cur == null) return;
+ Traversal(cur.left, res);
+ res.Add(cur.val);
+ Traversal(cur.right, res);
+}
+```
+```C#
+// 后序遍历
+public IList<int> PostorderTraversal(TreeNode root)
+{
+ var res = new List<int>();
+ if (root == null) return res;
+ Traversal(root, res);
+ return res;
+}
+public void Traversal(TreeNode cur, IList<int> res)
+{
+ if (cur == null) return;
+ Traversal(cur.left, res);
+ Traversal(cur.right, res);
+ res.Add(cur.val);
+}
+```
+
 <p>
 <a href="https://programmercarl.com/other/kstar.html">
 
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