HDU 2669 Romantic（扩展欧几里德）

Posted 2020-09-19 llguanli

题目链接：http://acm.hdu.edu.cn/showproblem.php?pid=2669

Problem Description

The Sky is Sprite.
The Birds is Fly in the Sky.
The Wind is Wonderful.
Blew Throw the Trees
Trees are Shaking, Leaves are Falling.
Lovers Walk passing, and so are You. 
................................Write in English class by yifenfei

 

Girls are clever and bright. In HDU every girl like math. Every girl like to solve math problem!
Now tell you two nonnegative integer a and b. Find the nonnegative integer X and integer Y to satisfy X*a + Y*b = 1. If no such answer print "sorry" instead.

 

Input

The input contains multiple test cases.
Each case two nonnegative integer a,b (0<a, b<=2^31)

 

Output

output nonnegative integer X and integer Y, if there are more answers than the X smaller one will be choosed. If no answer put "sorry" instead. 

 

Sample Input

77 51
10 44
34 79

 

Sample Output

2 -3
sorry
7 -3

 

Author

yifenfei

 

Source

HDU女生专场公开赛——谁说女子不如男

PS:

扩展欧几里德模板题。

附：扩展欧几里德解说：http://blog.csdn.net/u012860063/article/details/39760003

代码例如以下：

#include <cstdio>
#include <cstring>
#include <cmath>
typedef __int64 LL;

LL exgcd(LL a,LL b,LL &x,LL &y)
{
    if(b == 0)
    {
        x = 1;
        y = 0;
        return a;
    }
    LL r = exgcd(b,a%b,x,y);
    LL t = x;
    x = y;
    y = t-a/b*y;
    return r;
}

int main()
{
    LL a,b,x,y;
    while(scanf("%I64d%I64d",&a,&b)!=EOF)
    {
        LL d = exgcd(a,b,x,y);
        if(1%d)//不能整除
            printf("sorry\n");
        else
        {
            while(x<0)
                x+=b,y-=a;
            printf("%I64d %I64d\n",x,y);
        }
    }
    return 0;
}