https://leetcode.com/problems/k-closest-points-to-origin/
class Solution { public: static bool cmp(pair<int, int>a, pair<int, int>b) { return a.second < b.second; } vector<vector<int>> kClosest(vector<vector<int>>& points, int K) { int n = points.size(); vector<pair<int, int>>vm; vector<vector<int>> ans; for(int i=0; i<n; i++){ vm.push_back(make_pair(i, points[i][0]*points[i][0]+points[i][1]*points[i][1])); } sort(vm.begin(), vm.end(), cmp); for(int i=0; i<K; i++){ ans.push_back(points[vm[i].first]); //first下表是index。push_back进去的是一个vector } return ans; } };
