#include<iostream>
#include<stdio.h>

using namespace std;

__int64 X,Y,M,N,L;

int main()
{
	scanf("%I64d%I64d%I64d%I64d%I64d",&X,&Y,&M,&N,&L);
	__int64 i;
	__int64 step,offset,speed;
	if(X==Y)
	{
		cout<<"0"<<endl;
		return 0;
	}
	if(M==N)
	{
		cout<<"Impossible"<<endl;
		return 0;
	}
	if(X<Y&&M>N)
	{
		offset = Y-X;
		speed = M-N;
	}
	else if(X>Y&&M<N)
	{
		offset = X-Y;
		speed = N-M;
	}
	else if(X<Y&&M<N)
	{
		for(i=1;offset<=0;i++)
		{
			offset = X+L*i-Y;
		}
		speed = N-M;
	}
	else
	{
		for(i=1;offset<=0;i++)
		{
			offset = Y+L*i-X;
		}
		speed = M-N;
	}
	__int64 MaxLoop = 2100000000/L;
	for(i=0;i<MaxLoop;i++)
	{
		if((L*i+offset)%speed==0)
		{
			printf("%I64d\n",(L*i+offset)/speed);
			return 0;
		}
	}
	cout<<"Impossible"<<endl;
	return 0;
}

• Re:跟我的算法几乎一样，我也是WA。。= = (11) 0403100119 2011-07-22 14:36:16