（二叉树）路径和

Path Sum.py

@@ -0,0 +1,40 @@
+# Definition for a binary tree node.
+class TreeNode:
+    def __init__(self, x):
+        self.val = x
+        self.left = None
+        self.right = None
+
+
+class Solution:
+    def hasPathSum(self, root, sum):
+        """
+        :type root: TreeNode
+        :type sum: int
+        :rtype: bool
+        """
+
+        def dfs(root, tar):
+            if not root:
+                return
+            if root.val == tar and root.left is None and root.right is None:
+                global res
+                res = True
+                # print(23, res)
+                return
+            dfs(root.left, tar - root.val)
+            dfs(root.right, tar - root.val)
+
+        if not root:
+            return False
+        res = False
+        dfs(root, sum)
+        return res
+
+
+root = TreeNode(5)
+root.left = TreeNode(4)
+root.left.left = TreeNode(11)
+root.left.left.right = TreeNode(2)
+
+print(Solution().hasPathSum(root, 22))