杭电OJ异或题

#include<stdio.h>
#include<stdlib.h>
#include<string.h>
int main()
{
long long A;
int n, m, z, l;
int t,i,j,r=0;
long long sum = 0;
scanf_s("%d", &t);
for (i = 0; i < t; i++)
{
scanf_s("%d %d %d %d", &n, &m, &z, &l);
A = 0;
sum = 0;
for (j = 0; j < n; j++)
{
sum = sum^A;
A = (A * m + z) % l;
}
printf("%I64d\n", sum*2);
}
return 0;
}