UVA 11971(p335)----Polygon

#include<cstdio>#include<iostream>using namespace std;typedef unsigned long long ULL;int t,n,k,cas=0;ULL gcd(ULL a,ULL b){    return b==0?a:gcd(b,a%b);}int main(){    scanf("%d",&t);    while(t--)    {        ULL ans=1,tmp=1;        scanf("%d%d",&n,&k);        for(int i=1;i<=k;i++)            tmp*=2;        ans=tmp-k-1;        if(ans<0) ans=0;        ULL t=gcd(ans,tmp);        ans/=t;        tmp/=t;       // cout<<ans<<" "<<tmp<<endl;        printf("Case #%d: %llu/%llu\n",++cas,ans,tmp);    }    return 0;}