Example 1:

Input: points = [[1,3],[-2,2]], K = 1

Output: [[-2,2]]

Explanation:

The distance between (1, 3) and the origin is sqrt(10).

The distance between (-2, 2) and the origin is sqrt(8).

Since sqrt(8) < sqrt(10), (-2, 2) is closer to the origin.

We only want the closest K = 1 points from the origin, so the answer is just [[-2,2]].

Input: points = [[3,3],[5,-1],[-2,4]], K = 2

Output: [[3,3],[-2,4]]

(The answer [[-2,4],[3,3]] would also be accepted.)

class Solution {

public:

    static bool cmp(vector<long long> a, vector<long long> b){

        return a[] < b[];

    }

    vector<vector<int>> kClosest(vector<vector<int>>& points, int K) {

        vector<vector<int>> ret;

        vector<vector<long long>> dist;

        for(auto pv : points) {

            vector<long long> tmp = {pv[], pv[], pv[]*pv[] + pv[]*pv[]};

            dist.push_back(tmp);

        }

        sort(dist.begin(), dist.end(), cmp);

        for(int i=; i<K; i++){

            vector<int> tmp = {(int)dist[i][], (int)dist[i][]};

            ret.push_back(tmp);

        }

        return ret;

    }

};