xtu 1268 Strange Optimization 湘潭邀请赛I

Strange Optimization Bobo is facing a strange optimization problem. Given n,m, he is going to find a real number α such that f(12+α) is maximized, where f(t)=mini,j∈Z|in−jm+t|. Help him! Note: It can be proved that the result is always rational. Input The input contains zero or more test cases and is terminated by end-of-file. Each test case contains two integers n,m. 1≤n,m≤109 The number of tests cases does not exceed 104. Output For each case, output a fraction p/q which denotes the result. Sample Input 1 1 1 2 Sample Output 1/2 1/4 Note For the first sample, α=0 maximizes the function. Source XTU OnlineJudge

#include

#define ll __int64
ll gcd(ll a,ll b)
{
    return a%b==0?b:gcd(b,a%b);
}

int main()
{
    ll a,b;
    while(~scanf("%I64d %I64d",&a,&b))
    {
        printf("1/%I64d\n",2*a*b/gcd(a,b));
    }
    return 0;
}