Sliding Window Sum

1#include<bits/stdc++.h>
2using namespace std;
3#define int long long
4signed main(){
5  ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
6  int n,k; cin>>n>>k;
7  int arr[n];
8  int a,b,c; cin>>arr[0]>>a>>b>>c;
9  for(int i=1,x=arr[0];i<n;++i) arr[i]=(x*a+b)%c,x=arr[i];
10  int res=0,run=0;
11  for(int i=0;i<k;++i) run+=arr[i];
12  res^=run;
13  for(int i=k;i<n;++i){
14    run+=arr[i]-arr[i-k];
15    res^=run;
16  }
17  cout<<res<<'\n';
18  return 0;
19}