/*
 * @lc app=leetcode id=111 lang=cpp
 *
 * [111] Minimum Depth of Binary Tree
 */
/**
 * 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 minDepth(TreeNode *root)
    {
        if (root == NULL)
            return 0;
        int left = minDepth(root->left);
        int right = minDepth(root->right);
        return (left == 0 || right == 0) ? (left + right + 1) : min(left, right) + 1;
    }
};