From 8c53c48ea87fc2f02934799da6f659a7647eb268 Mon Sep 17 00:00:00 2001
From: Kelvin <guanli611@outlook.com>
Date: Thu, 29 Jul 2021 11:21:14 -0400
Subject: [PATCH] =?UTF-8?q?Revert=20"=E6=9B=B4=E6=96=B0=20513.=E6=89=BE?=
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This reverts commit 2f412e5c7d3b41b66946d92e699330cb7e5e5036.
---
 problems/0513.找树左下角的值.md | 61 +++++---------------------
 1 file changed, 12 insertions(+), 49 deletions(-)

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 391118ab..17d15fde 100644
--- a/problems/0513.找树左下角的值.md
+++ b/problems/0513.找树左下角的值.md
@@ -274,9 +274,8 @@ class Solution {
 
 
 Python：
-
-**递归法 - 回溯**
 ```python
+//递归法
 # Definition for a binary tree node.
 # class TreeNode:
 #     def __init__(self, val=0, left=None, right=None):
@@ -285,53 +284,17 @@ Python：
 #         self.right = right
 class Solution:
     def findBottomLeftValue(self, root: TreeNode) -> int:
-        max_depth = -float("INF")
-        max_left_value = -float("INF")
-
-        def __traversal(root, left_len): 
-            nonlocal max_depth, max_left_value
-
-            if not root.left and not root.right: 
-                if left_len > max_depth: 
-                    max_depth = left_len
-                    max_left_value = root.val
-                return 
-
-            if root.left: 
-                left_len += 1
-                __traversal(root.left, left_len)
-                left_len -= 1
-
-            if root.right: 
-                left_len += 1
-                __traversal(root.right, left_len)
-                left_len -= 1
-            return 
-        
-        __traversal(root, 0)
-
-        return max_left_value
-```
-
-**迭代法 - 层序遍历**
-```python
-class Solution:
-    def findBottomLeftValue(self, root: TreeNode) -> int:
-        queue = deque()
-        if root: 
-            queue.append(root)
-        result = 0
-        while queue: 
-            q_len = len(queue)
-            for i in range(q_len): 
-                if i == 0: 
-                    result = queue[i].val 
-                cur = queue.popleft()
-                if cur.left: 
-                    queue.append(cur.left)
-                if cur.right: 
-                    queue.append(cur.right)
-        return result
+        depth=0
+        self.res=[]
+        def level(root,depth):
+            if not root:return
+            if depth==len(self.res):
+                self.res.append([])
+                self.res[depth].append(root.val)
+            level(root.left,depth+1)
+            level(root.right,depth+1)
+        level(root,depth)
+        return self.res[-1][0]
 ```
 Go：