扩展欧几里得--hdu2669

hdu-2669

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 Xa + Yb = 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

题意

若存在满足ax+by=1的x，y，则输出非负整数x，整数y，否则输出sorry

#include <iostream>
#include <algorithm>
#include <string>
#include <cstring>
#include <cmath>
#include <vector>
#include <map>
#include <set>
#include <queue>
#include <stack>
#include <iomanip>
#include <cstdio>

using namespace std;
typedef long long LL;
typedef pair<double, double> PDD;
typedef pair<LL, LL> PLL;

const LL N = 1e6+50;
const LL MOD = 1e9+7;
const LL INF = 0x3f3f3f3f;

#define lson l, m, rt>>1
#define rson m+1, r, rt>>1|1

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

LL gcd(LL a, LL b)
{
    return b?gcd(b, a%b):a;
}

int main()
{
    LL a, b, x, y;
    while(cin >> a >> b)
    {
        if(gcd(a, b) != 1) puts("sorry");
        else
        {
            exgcd(a, b, x, y);
            while(x < 0)
            {
                x += b;y -= a;
            }
            cout << x << " " << y << endl;
        }
    }
    return 0;
}