LeetCode(42) Maximum Depth of Binary Tree

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题目描述

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.

题目要求计算一棵二叉树的高度。本题最简单的解法是递归计算左右子树的高度，并在左右子树高度的最大值的基础上加1，则得到本层到叶子节点的高度。

解题代码

/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
 * };
 */
class Solution {
public:
    int maxDepth(TreeNode* root) {
        if (root == NULL)
            return 0;

        int left = 0, right = 0;
        if (root != NULL)
        {
            if(root->left != NULL)
                left = maxDepth(root->left);
            if(root->right != NULL)
                right = maxDepth(root->right);
        }
        return max(left,right)+1;
    }
};