簡單題，直接模擬即可
#include <iostream>
#include <cmath>
const int MAXN = 151;
int tx, ty, n, i, j, k, max, x[MAXN], y[MAXN];
float r, d;
float dist(int i)
{
return sqrt((x[i] - tx) * (x[i] - tx) + (y[i] - ty) * (y[i] - ty));
}
bool insc(int i, int j)
{
if ((tx - x[i]) * (ty - y[j]) - (tx - x[j]) * (ty - y[i]) >= 0) return true;
else return false;
}
int main()
{
while (scanf("%d%d%f", &tx, &ty, &r), r > 0)
{
scanf("%d", &n);
j = 0;
for (i = 1; i <= n; i++)
{
scanf("%d%d", &x[0], &y[0]);
d = dist(0);
if (d <= r) {
j++;
x[j] = x[0];
y[j] = y[0];
}
}
n = j;
max = 0;
for (i = 1; i <= n; i++)
{
k = 0;
for (j = 1; j <= n; j++) if (insc(i, j)) k++;
max >?= k;
}
printf("%d\n", max);
}
return 0;
}