513. Find Bottom Left Tree Value 二叉树左下节点的值

Given a binary tree, find the leftmost value in the last row of the tree.

Example 1:

Input:

    2
   / \
  1   3

Output:
1

Example 2: 

Input:

        1
       / \
      2   3
     /   / \
    4   5   6
       /
      7

Output:
7

Note: You may assume the tree (i.e., the given root node) is not NULL.

求二叉树左下方节点的值，使用广度优先遍历，每遍历一层刷新result值

  1. class Solution(object):
  2.     def findBottomLeftValue(self, root):
  3.         """
  4.         :type root: TreeNode
  5.         :rtype: int
  6.         """
  7.         left = 0
  8.         if(not root):
  9.             return left
  10.         result = []
  11.         queue = [root]
  12.         while(queue):
  13.             count = len(queue)
  14.             for i in range(0, count):
  15.                 node = queue.pop(0)
  16.                 if i == 0:
  17.                     left = node.val
  18.                 if(node.left):
  19.                     queue.append(node.left)
  20.                 if(node.right):
  21.                     queue.append(node.right)
  22.         return left





posted @ 2017-08-13 22:28  xiejunzhao  阅读(215)  评论(0)  编辑  收藏  举报