Uva10673 - Play with Floor and Ceil ( 扩展欧几里定理 )

#include <cstdio>
#include <cstring>
#include <algorithm>
#include <cmath>
using namespace std;
typedef long long LL;
void ex_gcd(LL a, LL b, LL &d, LL &x, LL &y)
{
    if(!b)
    {
        d = a;
        x = 1, y = 0;
        return;
    }
    else
    {
        ex_gcd(b, a%b, d, y, x);
        y -= x * (a / b);
        return;
    }
}

void Orz()
{
    int cas = 0;
    LL a, b, x, y, d, c, X, K ;
    scanf("%d",&cas);
    while(cas--)
    {
        scanf("%lld %lld",&X,&K);
        //a = (LL)ceil(1.0*X/K);  搞反了，，擦 
        //b = (LL)floor(1.0*X/K);
        a = (LL)floor(1.0*X/K);
        b = (LL)ceil(1.0*X/K);
        ex_gcd(a, b, d, x, y);
        x = x * X / d;
        y = y * X / d;
        printf("%lld %lld\n",x,y);
    }
}

int main()
{
    Orz();
    return 0;
}