Leetcode--Minimum 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.

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思路：记忆深搜获取所有叶子节点的深度，保存到vector中。再将容器的元素排序，结果返回第一个元素

/** * Definition for binary tree * struct TreeNode { *     int val; *     TreeNode *left; *     TreeNode *right; *     TreeNode(int x) : val(x), left(NULL), right(NULL) {} * }; */class Solution {public:    vector<int> res;    void function(TreeNode *root,int num)    {        if(root==NULL)            res.push_back(num);        else{            int temp=num+1;            if(root->left==NULL&&root->right==NULL)                function(root->left,temp);            else if(root->left!=NULL&&root->right==NULL)                function(root->left,temp);            else if(root->left==NULL&&root->right!=NULL)                function(root->right,temp);            else{                function(root->left,temp);                function(root->right,temp);            }        }    }    int minDepth(TreeNode *root) {        if(root==NULL)              return 0;        function(root,0);        sort(res.begin(),res.end());        return res[0];    }};