poj 2301 Beat the Spread!

#include <cstdio>#include <cstdlib>int main(){    long long n,s,d,a,b;    scanf("%I64d",&n);    for (long long t=0; t<n; t++)    {        scanf("%I64d%I64d",&s,&d);        if ((s+d)&1)        { printf("impossiblen"); continue;        }        a=(s+d)/2;        b=s-a;        if (a<0||b<0)        { printf("impossiblen"); continue;        }        a<b?printf("%I64d %I64dn",b,a):printf("%I64d %I64dn",a,b);    }    return 0;}