HDU 5344 多校赛1002 MZL's xor

Problem Description

MZL loves xor very much.Now he gets an array A.The length of A is n.He wants to know the xor of all (Ai+Aj)(1≤i,j≤n)The xor of an array B is defined as B1 xor B2...xor Bn

Input

Multiple test cases, the first line contains an integer T(no more than 20), indicating the number of cases.Each test case contains four integers:n,m,z,lA1=0,Ai=(Ai−1∗m+z) mod l1≤m,z,l≤5∗105,n=5∗105

Output

For every test.print the answer.

Sample Input

23 5 5 76 8 8 9

Sample Output

1416

#include <iostream>using namespace std;long long a[500001];int main(){    int T;    long long n,m,z,l;    while(cin>>T)    {        while(T--)        {            cin>>n>>m>>z>>l;            a[1] = 0;            for(int i=2;i<=n;i++)            {                a[i] = (a[i-1] * m + z) % l;            }            int sum = a[1];            for(int i=2;i<=n;i++)            {                sum ^= a[i]*2;            }            cout<<sum<<endl;        }    }    return 0;}