亚麻:k closest points

 

the original point is considered as the (0,0);

#include <iostream>     // std::cout
#include <algorithm>    // std::make_heap, std::pop_heap, std::push_heap, std::sort_heap
#include <vector>       // std::vector
#include <unordered_map>
#include <map>
#include <numeric>
#include <list>
#include <numeric>
#include <utility>
//key point
//use multimap < distance , point > to store <distance , point> pair in ascending order .

//then out the points with Kth distance.
using namespace std;

struct point{
    int x;
    int y;
    
    point(int x, int y ):x(x),y(y){}
};

list<point> KclosePoint (list<point>& points, int K ){
    
    if ( points.empty()) return list<point>();
    
    if (points.size () < K) return points;
    
    multimap<float , point> dist;
    
    for (auto& e: points){  // the distance will be sorted automatically
        dist.insert( make_pair (sqrt(pow(e.x,2) + pow(e.y,2)), e));
    }
    for (auto& e: dist)
        cout <<" dist "<< e.first << endl;
    
    list<point> res;
    
    int index =0;
    auto itor = dist.begin();
    while (index < K){
        res.push_back(itor->second);
        itor++;
        index++;
    }
    
    return res;
    
}
int main () {
    list<point> in = {{9,9}, {10,10},{1,1},{2,2},{3,3},{4,4},{5,5}};
    //sort(in.begin(),in.end());
    auto out = KclosePoint(in,0);
    for (auto& e: out )
        cout<< e.x <<" " << e.y << endl;
    return 0;
}

 

posted @ 2018-01-17 14:49  HisonSanDiego  阅读(239)  评论(0编辑  收藏  举报