一直WA,很郁闷。

#include <stdio.h>

long long ext_euclid(long long a,long long b,long long* x,long long* y)
{
  long long t,d;

  if (b==0) {
    *x=1;
    *y=0;
    return a;
  }
  d=ext_euclid(b,a%b,x,y);
  t=*x;
  *x=*y;
  *y=t-a/b*(*y);
  return d;
}

long long modular_linear(long long a,long long b,long long n)
{
  long long d,x,y;
  
  d=ext_euclid(a,n,&x,&y);
  if (b%d>0) return 0;
  return x*(b/d);
}

int main()
{
  int m,n,x,y,l;
  long long ans;

  scanf("%d %d %d %d %d",&x,&y,&m,&n,&l);
  if (m==n || !(ans=modular_linear(m-n,y-x,l)))
    printf("Impossible\n");
  else
    printf("%lli\n",ans+(ans<0)*l);
  return 0;
}

• Re:跪求高手来看看啊....... (754) Try0401 2007-01-20 14:51:14