2.11寻找最近的点对 （给定一系列的点，求出距离最短的点对）

#include<iostream>#include<vector>#include<algorithm>using namespace std;/*int pow(int a,int index){int result=1;int temp=a;for(;index;index>>=1){if(index&1)result*=temp;temp*=temp;}return result;}*//*bool aa(int a,int b){return a<b;}*/class Point{public:  Point(int x,int y):x_(x),y_(y){}Point():x_(0),y_(0){} static bool OrderByX(const Point& left, const Point& right) {     return left.x_ < right.x_;     }    static bool OrderByY(const Point& left, const Point& right) {       return left.y_ < right.y_;     }     int x_;     int y_;   };  float Distance(const Point& left, const Point& right){  return sqrt(pow(float(left.x_ - right.x_), 2) + pow(float(left.y_ - right.y_), 2));  }; int NearestPoints(const std::vector<Point>& points, int start, int end, Point* point1, Point* point2) {   if (end > start)    {        int middle = (start + end) / 2;        int left_min_distance = NearestPoints(points, start, middle, point1, point2);      int right_min_distance = NearestPoints(points, middle + 1, end, point1, point2);        int min_distance = left_min_distance > right_min_distance ? right_min_distance : left_min_distance;         std::vector<Point> left_part_points;    for (int i = start; i <= middle; ++i)  {       if (points[middle].x_ - points[i].x_ <= min_distance)  {         left_part_points.push_back(points[i]);       }     }        sort(left_part_points.begin(), left_part_points.end(), Point::OrderByY);        std::vector<Point> right_part_points;     for (int i = middle + 1; i <= end; ++i)    {       if (points[i].x_ - points[middle].x_ <= min_distance) {         right_part_points.push_back(points[i]);       }     }     sort(right_part_points.begin(), right_part_points.end(), Point::OrderByY);     int distance_y = 0;     int point_distance = 0;     for(int i = 0; i < left_part_points.size(); ++i)    {       for(int j = 0; j < right_part_points.size(); ++j)  {         distance_y = left_part_points[i].y_ > right_part_points[j].y_ ? left_part_points[i].y_ - right_part_points[j].y_ :                      right_part_points[j].y_ - left_part_points[i].y_;         if (distance_y <= min_distance)    {          point_distance = Distance(left_part_points[i], right_part_points[j]);           if (point_distance < min_distance) {             min_distance = point_distance;             *point1 = left_part_points[i];             *point2 = right_part_points[j];           }         }       }     }    return min_distance;     }    else   {      return 0x7FFFFFFF;     }   }int main(){std::vector<Point> points;   points.push_back(Point(2,3));   points.push_back(Point(1,4));   points.push_back(Point(3,0));   points.push_back(Point(5,0));       points.push_back(Point(5,1));       sort(points.begin(), points.end(), Point::OrderByX);       Point point1;       Point point2;      NearestPoints(points, 0, points.size() - 1, &point1, &point2);       printf("Point1: (%d, %d) <--> Point2: (%d, %d)\n", point1.x_, point1.y_, point2.x_, point2.y_);       system("pause"); return 0;}