Merge pull request #2341 from eeee0717/master

Update 0257.二叉树的所有路径，添加C#递归

problems/0112.路径总和.md

@@ -1511,6 +1511,17 @@ impl Solution {
     }
 }
 
+```
+### C#
+```C#
+// 0112.路径总和
+// 递归 
+public bool HasPathSum(TreeNode root, int targetSum)
+{
+    if (root == null) return false;
+    if (root.left == null && root.right == null && targetSum == root.val) return true;
+    return HasPathSum(root.left, targetSum - root.val) || HasPathSum(root.right, targetSum - root.val);
+}
 ```
 
 <p align="center">

problems/0257.二叉树的所有路径.md

@@ -900,6 +900,43 @@ impl Solution {
     }
 }
 ```
+### C#
+```C#
+public IList<string> BinaryTreePaths(TreeNode root)
+{
+    List<int> path = new();
+    List<string> res = new();
+    if (root == null) return res;
+    Traversal(root, path, res);
+    return res;
+}
+public void Traversal(TreeNode node, List<int> path, List<string> res)
+{
+    path.Add(node.val);
+    if (node.left == null && node.right == null)
+    {
+        string sPath = "";
+        for (int i = 0; i < path.Count - 1; i++)
+        {
+            sPath += path[i].ToString();
+            sPath += "->";
+        }
+        sPath += path[path.Count - 1].ToString();
+        res.Add(sPath);
+        return;
+    }
+    if (node.left != null)
+    {
+        Traversal(node.left, path, res);
+        path.RemoveAt(path.Count-1);
+    }
+    if (node.right != null)
+    {
+        Traversal(node.right, path, res);
+        path.RemoveAt(path.Count-1);
+    }
+}
+```
 
 <p align="center">
 <a href="https://programmercarl.com/other/kstar.html" target="_blank">

problems/0404.左叶子之和.md

@@ -651,6 +651,23 @@ impl Solution {
     }
 }
 ```
+### C#
+```C#
+// 递归
+public int SumOfLeftLeaves(TreeNode root)
+{
+    if (root == null) return 0;
+
+    int leftValue = SumOfLeftLeaves(root.left);
+    if (root.left != null && root.left.left == null && root.left.right == null)
+    {
+        leftValue += root.left.val;
+    }
+    int rightValue = SumOfLeftLeaves(root.right);
+    return leftValue + rightValue;
+
+}
+```
 
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problems/0513.找树左下角的值.md

@@ -684,6 +684,38 @@ impl Solution {
     }
 }
 ```
+### C#
+```C#
+//递归
+int maxDepth = -1;
+int res = 0;
+public int FindBottomLeftValue(TreeNode root)
+{
+    Traversal(root, 0);
+    return res;
+}
+public void Traversal(TreeNode root, int depth)
+{
+    if (root.left == null && root.right == null)
+    {
+        if (depth > maxDepth)
+        {
+            maxDepth = depth;
+            res = root.val;
+        }
+        return;
+    }
+    if (root.left != null)
+    {
+        Traversal(root.left, depth + 1);
+    }
+    if (root.right != null)
+    {
+        Traversal(root.right, depth + 1);
+    }
+    return;
+}
+```
 
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