[leetcode]111. Minimum Depth of Binary Tree

题目链接：https://leetcode.com/problems/minimum-depth-of-binary-tree/#/description

Given a binary tree, find its minimum depth.

The minimum depth is the number of nodes along the shortest path from the root node down to the nearest leaf node.

class Solution {
public:
    int minDepth(TreeNode * root) {
        // write your code here
        if(!root)
            return 0;
        if(!root->left && !root->right)
            return 1;
        int left=minDepth(root->left);
        if(left == 0)
            left = INT32_MAX;
        int right=minDepth(root->right);
        if(right == 0)
            right = INT32_MAX;
        return min(left, right)+1;
    }

};

class Solution {
public:
    int minDepth(TreeNode *root) {
        if(!root) return 0;
        if(!root->left) return 1 + minDepth(root->right);
        if(!root->right) return 1 + minDepth(root->left);
        return 1+min(minDepth(root->left),minDepth(root->right));
    }
};