[Leetcode] Maximum Depth of Binary Tree

Maximum Depth of Binary Tree 题解

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题目来源：https://leetcode.com/problems/maximum-depth-of-binary-tree/description/

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Description

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.

Solution

class Solution {
public:
    int maxDepth(TreeNode* root) {
        if (root == NULL) return 0;
        int res = 0;
        queue<TreeNode*> q;
        q.push(root);
        q.push(NULL);
        while (!q.empty()) {
            TreeNode* node = q.front();
            q.pop();
            if (node != NULL) {
                if (node -> left != NULL)
                    q.push(node -> left);
                if (node -> right != NULL)
                    q.push(node -> right);
            } else {
                res++;
                if (!q.empty())
                    q.push(NULL);
            }
        }
        return res;
    }
};

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解题描述

这道题题意是求二叉树的深度，上面的解法用到的是迭代法层次遍历来计算二叉树深度，使用的方法和层次遍历相近。