为什么

#include <cstdio>
#include <iostream>
#include <cstring>
#include <algorithm>

using namespace std;

typedef long long LL;

LL a, b, x, y, d;

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

int main(){
    while(~scanf("%lld%lld", &a, &b)){
        d = exgcd(a, b, x, y);
        //if(x > y) swap(x, y);
        printf("%lld %lld %lld\n", x, y, d);
    }
    return 0;
}

能过

但

#include <cstdio>
#include <iostream>
#include <cstring>
#include <algorithm>

using namespace std;

typedef long long LL;

LL a, b, x, y, d;

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

int main(){
    while(~scanf("%lld%lld", &a, &b)){
        d = exgcd(a, b, x, y);
        if(x > y) swap(x, y);
        printf("%lld %lld %lld\n", x, y, d);
    }
    return 0;
}

会WA啊