// https://leetcode.com/problems/minimum-depth-of-binary-tree/

/**
 * 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 {
private:
    int min = 100001;
public:
    int minDepth(TreeNode* root) {
        if (root == nullptr) return 0;
        return minDepth(root, 1);
    }
    int minDepth(TreeNode* root, int current) {
        if (root == nullptr) {
            return min;
        } else {
            if (root->left == nullptr && root->right == nullptr && current < min) {
                min = current;
            }
            minDepth(root->left, current + 1);
            minDepth(root->right, current + 1);
        }
        return min;
    }
};