Leetcode 104. Maximum Depth of Binary Tree

문제 : 104. Maximum Depth of Binary Tree

등급 : Easy

class Solution {
    int stepDown(TreeNode * root, int depth) {
        if (!root) return depth;
        
        depth += 1;
        
        auto ldepth = stepDown(root->left, depth);
        auto rdepth = stepDown(root->right, depth);
        
        depth = std::max(depth, ldepth);
        depth = std::max(depth, rdepth);
        
        return depth;
    }
    
public:
    int maxDepth(TreeNode* root) {
        return stepDown(root, 0);
    }
};