3174365_ac_670ms_62896k.cc

北大大牛代码 1240道题的原代码 超级权威

#include <stdio.h>

int mark[16000000];

int main()
{
	int i, flag, last;
	int a, c, m, r0, ans;

	scanf("%d%d%d%d",&a,&c,&m,&r0);
	flag = 1;
	mark[r0] = flag;
	if(c >= m)
		c %= m;
	if(a >= m)
		a %= m;
	while(1)
	{
		r0 = (a*r0+c)%m;
		if(mark[r0]==flag)
			break;
		else
			mark[r0] = flag;
	}
	last = -1;
	ans = 0;
	for(i = 0; i < m; i++)
	{
		if(mark[i]==flag)
		{
			if(last!=-1&&i-last>ans)
			{
				ans = i-last;
			}
			last = i;
		}
	}
	printf("%d\n",ans);
	return 0;
}