leetcode--Minimum Depth of Binary Tree

1.题目描述

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.

2.解法分析

/**
 * Definition for binary tree
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
 * };
 */
class Solution {
public:
    int minDepth(TreeNode *root) {
        // Start typing your C/C++ solution below
        // DO NOT write int main() function
        if(root == NULL)return 0;

        if(!root->left&&!root->right)return 1;
        if(root->left&&root->right)
        {
            return min(minDepth(root->left),minDepth(root->right))+1;
        }
        else
        {
            if(root->left)return minDepth(root->left)+1;
            else return minDepth(root->right)+1;
        }


    }
};