南阳理工OJ_题目710 外星人的供给站

#include <iostream>#include <stdlib.h>#include <math.h>//贪心算法 //把点转换成区间//去掉大区间//贪心开始... using namespace std;struct seat{int x;//int y;//坐标 double left;//double right;//区间 int flag;//标记，0为去掉 };int cmp(const void *_a, const void *_b);bool is_in(seat a, double xy, int r);int main(){int k;cin >> k;while(k--){seat a[110];int n, r;cin >> n >> r;for (int i = 0; i < n; i++){cin >> a[i].x >> a[i].y;a[i].flag = 1;a[i].left = a[i].x - sqrt(r*r - a[i].y*a[i].y);a[i].right = a[i].x + sqrt(r*r - a[i].y*a[i].y);}qsort(a, n, sizeof(seat), cmp);//按照区间左值排序 for(int i = 0; i < n; i++)//去除大区间 {for(int j = i+1; j < n; j++){if(a[i].flag == 1 && a[i].left <= a[j].left && a[i].right >= a[j].right)a[i].flag = 0;}}int count = 0;double current;for(int i = 0; i < n; i++){if(a[i].flag == 1){current = a[i].right;count++;a[i].flag = 0;for(int j = i+1; j < n; j++){if(a[j].left <= current && a[j].right >= current)a[j].flag = 0;}}}cout << count << endl;}}int cmp(const void *_a, const void *_b){seat *a;seat *b;a = (seat *)_a;b = (seat *)_b;if(a->left > b->left)return 1;if(a->left == b->left)return 0;if(a->left < b->left)return -1;}