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

 

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

 

实际上是一道很裸的扩展欧几里德定理的题目，结果把Floor和Ceil搞反了WA一次悲剧啊

#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;

}