[81][E][leetcode 题解]Minimum Depth of Binary Tree

Given a binary tree, find its minimum depth.

The minimum depth is the number of nodes along the shortest path from the root node down to the nearest leaf node.

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有一个点就是，如果它不是叶子节点，不能算。这个地方容易犯错。

class Solution(object):
    def __init__(self):
        self.minn = 99999
    def dfs(self,root,lenn):
        if root.left  == None and root.right == None:
            self.minn = min(lenn,self.minn)
            return
        if root.left:
            self.dfs(root.left,lenn+1)
        if root.right:
            self.dfs(root.right,lenn+1)

    def minDepth(self, root):
        if not root:
            return 0
        self.dfs(root,1)
        #print self.minn
        return self.minn