Create distribute-coins-in-binary-tree.py

Author: kamyu104

Python/distribute-coins-in-binary-tree.py

@@ -0,0 +1,27 @@
+# Time:  O(n)
+# Space: O(h)
+
+# Definition for a binary tree node.
+class TreeNode(object):
+    def __init__(self, x):
+        self.val = x
+        self.left = None
+        self.right = None
+
+        
+class Solution(object):
+    def distributeCoins(self, root):
+        """
+        :type root: TreeNode
+        :rtype: int
+        """
+        def dfs(root, result):
+            if not root:
+                return 0
+            left, right = dfs(root.left, result), dfs(root.right, result)
+            result[0] += abs(left) + abs(right)
+            return root.val + left + right - 1
+
+        result = [0]
+        dfs(root, result)
+        return result[0]