uva 10056
概率 Q += p*pow(1-p, i*n+k-1) i = 0,1,2,3......
#include <cstdio> #include <cmath> int main () { int t; scanf("%d",&t); while(t--) { int n,k; double p; scanf("%d%lf%d",&n,&p,&k); double ans = p*pow(1-p, k-1), cc = 0; int i = 1; while(ans - cc > 1e-9) { cc = ans; ans += p*pow(1-p, n*i+k-1); i++; } printf("%.4lf\n",ans); } return 0; }