Maximum_Depth_Of_Binary_Tree.cpp

#include "algorithm"
using namespace std;

// Definition for a binary tree node.
struct TreeNode {
    int val;
    TreeNode *left;
    TreeNode *right;
    TreeNode() : val(0), left(nullptr), right(nullptr) {}
    TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
    TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
};

class Solution {
public:
    int maxDepth(TreeNode* root) {
        if (root == nullptr) {
            return 0;
        }
        return traverse(root, 1);
    }

    int traverse(TreeNode* root, int count) {
        if (root == nullptr) {
            return count-1;
        }

        int leftDepth = traverse(root->left, count+1);
        int rightDepth = traverse(root->right, count+1);
        return max(leftDepth,rightDepth);
    }   
};