play with floor and seil(extended euclid matrix application)

#include <iostream>
#include <cstdio>
#include <cmath>
#include <utility>

using namespace std;

long long gcd(long long a, long long b)
{
    if(b == 0)return a;
    else gcd(b, a%b);
}

pair<long long, long long> eucl(long long a, long long b)
{
    pair<long long, long long> p;
    long long matr[2][3], q;            ///[a 1 0]
                                        ///[b 0 1]
    matr[0][0] = a;
    matr[0][1] = 1;
    matr[0][2] = 0;

    matr[1][0] = b;
    matr[1][1] = 0;
    matr[1][2] = 1;

    while(1){
        if(matr[0][0] == 0){
            p.first = matr[1][1];
            p.second = matr[1][2];
            return p;
        }
        else if(matr[1][0] == 0){
            p.first = matr[0][1];
            p.second = matr[0][2];
            return p;
        }

        if(a > b){
            q = a/b;
            matr[0][0] -= matr[1][0]*q;
            matr[0][1] -= matr[1][1]*q;
            matr[0][2] -= matr[1][2]*q;
        }
        else if(a < b){
            q = b/a;
            matr[1][0] -= matr[0][0]*q;
            matr[1][1] -= matr[0][1]*q;
            matr[1][2] -= matr[0][2]*q;
        }

        a = matr[0][0];
        b = matr[1][0];
    }
}

int main()
{
    long long x, k, p, q, a, b, t, g;
    pair<long long, long long>pa;
    scanf("%lld", &t);
    while(t--){
        scanf("%lld %lld", &x, &k);
        a = floor(((double)x/(double)k));
        b = ceil(((double)x/(double)k));
        g = gcd(max(a, b), min(a, b));
        if(a == b){
            p = 0;
            q = 1;
        }
        else{
            pa = eucl(a, b);
            p = pa.first;
            q = pa.second;
        }

        printf("%lld %lld\n", x*p/g, x*q/g);
    }
    return 0;
}