hdu acm-step 2.1.5 又见GCD

#include <cstdio>
using namespace std;
int gcd(int a,int b)
{
        int r;
        while(b)
        {
                r = a%b;
                a = b;
                b = r;
        }
        return a;
}
int main()
{
        int T;
        scanf("%d",&T);
        while(T--)
        {
                int a,b;
                scanf("%d%d",&a,&b);
                int t = a/b;
                int i;
                for(i=2;i<t;i++){if(gcd(a,i*b) == b)break;}
                if(i==t)
                while(gcd(i*b,a)!=b)i++;
                printf("%d\n",i*b);

        }
        return 0;
}