Maximum Depth of Binary Tree

题目链接:http://oj.leetcode.com/problems/maximum-depth-of-binary-tree/

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.

解法:递归;父节点的深度等于左子树/右子树中深度大者+1

/**
 * Definition for binary tree
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
 * };
 */
class Solution {
public:
    int maxDepth(TreeNode *root) {
        // IMPORTANT: Please reset any member data you declared, as
        // the same Solution instance will be reused for each test case.
        int l, r;
        if (root == NULL)
            return 0;
        else if ((l = maxDepth(root->left)) > (r = maxDepth(root->right)))
            return l + 1;
        else
            return r + 1;
    }
};