poj 1106 Transmitters

poj 1106 Transmitters

#include <iostream>#include <stdio.h>#include <stdlib.h>#include <string.h>#include <math.h>#include <algorithm>using namespace std;#define maxn 200#define eps 1.0e-8struct Point{    int x, y;}s, point[maxn];double r;int n;bool operator < (const Point &a, const Point &b){    return atan2((double)a.x, (double)a.y) < atan2((double)b.x, (double)b.y);}void input(){    int cnt = 0;    scanf("%d", &n);    for (int i = 0; i < n; i++)    {        scanf("%d%d", &point[cnt].x, &point[cnt].y);        point[cnt].x -= s.x;        point[cnt].y -= s.y;        if (r * r > point[cnt].x * point[cnt].x + point[cnt].y * point[cnt].y - eps) cnt++;    }    n = cnt;}double xmulti(Point a, Point b){    return a.x * b.y - a.y * b.x;}bool within(Point a, Point b){    return xmulti(b, a) > -eps;}int work(){    int r = 0;    int ans = 0;    for (int i = 0; i < n; i++)    {        while (r - i < n && within(point[i], point[r % n])) r++;        ans = max(ans, r - i);    }    return ans;}int main(){    while (scanf("%d%d%lf", &s.x, &s.y, &r), r >= 0)    {        input();        sort(point, point + n);        printf("%dn", work());    }    return 0;}