hdu 5344 MZL's xor

 1 #include<cstdio>
 2 #include<cstring>
 3 using namespace std;
 4 int main()
 5 {
 6     long long t,n,m,z,l,a,sum;
 7     scanf("%I64d",&t);
 8     while (t--)
 9     {
10         scanf("%I64d%I64d%I64d%I64d",&n,&m,&z,&l);
11         a=sum=0;
12         n-=1;
13         while (n--)
14         {
15             a=(m*a+z)%l;
16             sum^=a*2;
17         }
18         printf("%I64d\n",sum);
19     }
20 }