LeetCode 111. 二叉树的最小深度

/**
 * 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)return 0;
        int res=INT_MAX;
        if(root->left)res=min(res,minDepth(root->left)+1);
        if(root->right)res=min(res,minDepth(root->right)+1);
        if(res==INT_MAX)res=1;
        return res;
    }
};