LeetCode104. Maximum Depth of Binary Tree

題目

原題鏈接

• https://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.

Note: A leaf is a node with no children.

Example:

Given binary tree [3,9,20,null,null,15,7],

    3
   / \
  9  20
    /  \
   15   7

return its depth = 3.

解題方案

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

執行用時24ms，內存消耗19MB。