leetcode45:maximum depth of binary tree

题目描述

求给定二叉树的最大深度，

最大深度是指树的根结点到最远叶子结点的最长路径上结点的数量。

Given a binary tree, find its maximum depth.

The maximum depth is the number of nodes along the longest path from the root node down to the farthest leaf node.

示例1

输入

复制

{1,2}

输出

复制

2

示例2

输入

/**
 * struct TreeNode {
 *    int val;
 *    struct TreeNode *left;
 *    struct TreeNode *right;
 * };
 */

class Solution {
public:
    /**
     *
     * @param root TreeNode类
     * @return int整型
     */
    int maxDepth(TreeNode* root) {
        // write code here
        if (root==NULL){return 0;}
        queue<TreeNode*> que;
        que.push(root);
        int depth=0;
        while (!que.empty()){
            int size=que.size();
            depth++;
            for (int i=0;i<size;++i){
                TreeNode *tmp=que.front();
                que.pop();
                if (tmp->left !=NULL)
                    que.push(tmp->left);
                if (tmp->right !=NULL)
                    que.push(tmp->right);
            }
        }
        return depth;
    }
};