Leetcode No.104 Maximum Depth of Binary Tree 遍历二叉树的深度

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.

注：题库和图片转自 www.leetcode.com ，所有权归www.leetcode.com仅供交流学习使用，不得用于商业用途

-----------------------------------------------------------------------------------------------------

我的解法：

/**
 * 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) {
        int currentDepth = 0;
        maxDep = 0;
        if(root != NULL)
        {
            travelBinaryTree(root, currentDepth);
        }
        return maxDep;
    }
private:
    int maxDep;
    void travelBinaryTree(TreeNode* node, int depth)
    {
        depth++;
        maxDep = (depth > maxDep) ? depth : maxDep;
        if(node->left)
            travelBinaryTree(node->left, depth);
        if(node->right)
            travelBinaryTree(node->right, depth);
    }
};

虽然结果正确，看了一下bbs上的讨论，感觉算法虽然不复杂但是太多代码冗余，leetcode上比较精简的一种解法

class Solution {
public:
    int maxDepth(TreeNode* root) {
        if (!root)
            return 0;
        return 1 + max(maxDepth(root->right), maxDepth(root->left));
    }
};

利用return的时候累加+1和max宏取最大值来获得最精简的代码。