UVa11971 - Polygon(连续概率)

紫书上推出来的公式1-(k+1)/2^(k)

注意范围 都用的long long

#include<cstdio>
#include<iostream>
#include<cmath>
using namespace std;
typedef long long ll;
ll gcd(ll a,ll b){
    return b==0?a:gcd(b,a%b);
}
int main()
{
    int n,kase=1;
    scanf("%d",&n);
    while(n--){

        ll N,K;
        scanf("%lld%lld",&N,&K);
        printf("Case #%d: ",kase++);
        ll a = ((ll)1<<K) - K - 1;
        ll b = ((ll)1<<K);
        if(a==0)
        printf("0/1\n");
        else {
            ll gd=gcd(a,b);
            a/=gd;
            b/=gd;
            printf("%lld/%lld\n",a,b);
        }

    }
    return 0;
}

UVa11971 - Polygon(连续概率)

原文：http://blog.csdn.net/a197p/article/details/45580497