poj 2959 Ball bearings

#include <iostream>#include <cstdlib>#include <cstring>#include <cstdio>#include <cmath>using namespace std;#define pi acos(-1)double d, D, r, s;int main(){    int t;    scanf("%d", &t);    while (t--)    {        scanf("%lf%lf%lf", &D, &d, &s);        d /= 2;        D /= 2;        r = D - d;        d = 2 * d + s;        int ans = (int)(2 * pi / acos((r * r * 2 - d * d) / (2 * r * r)));        printf("%dn", ans);    }    return 0;}