LeetCode:Minumum Depth of Binary Tree

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.

 

/**
 * 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) {
    //深搜递归
    
        if(root==NULL) return 0;
        if(!root->left&&!root->right)
            return 1;
        int leftdepth=minDepth(root->left);
        int rightdepth=minDepth(root->right);
        if(leftdepth==0)
            return rightdepth+1;
        else if(rightdepth==0)
            return leftdepth+1;
        else
            return min(leftdepth,rightdepth)+1;
    }
};