等差数列异或和模板

#include <iostream>
#include<algorithm>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <queue>
#define INF 0x3f3f3f3f
#define DOF 0x7f7f7f7f
#define mem(a,b) memset(a,b,sizeof(a))
typedef long long LL;
using namespace std;
LL f (LL a,LL b,LL c,LL n)//首项  公差  c  项数
{

    if (n==0) return 0;
    LL ans=(b/c)*n*(n-1)/2+(a/c)*n;
    ans=ans+f((b*n+a)%c,c,b%c,((b%c)*n+(a%c))/c);
    return ans;
}
int main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    LL x,y,z,k;
    while(cin>>x>>y>>z)//x-首项  y-最后一项 x+kz<=y |   z-公差
    {
        LL ans=0;
        k=(y-x)/z;
        for (LL u=0;u<32;u++)
        ans=ans|((f(x,z,(1LL<<u),k+1)&1LL)<<u);
        cout<<ans<<endl;
    }
    return 0;
}