不知道取什么名字

#include<bits/stdc++.h>
#pragma GCC optimize(3)
using namespace std;
typedef long long ll;
typedef double db;
ll n,t,d,k;
ll a,c;
int main()
{

    scanf("%lld",&t);
    while(t--)
    {
        scanf("%lld%lld%lld%lld",&n,&a,&d,&k);
        c=ceil(cbrt(a));
        if(c*c*c<a)
        {
            c=c+1;
        }
        ll sum=c*n;
        for(ll i=2; i<=n; i++)
        {
            a=a+d+(i-2)*k;
            while(c*c*c<a)c++;
            sum=sum^(c*(n-i+1));
        }
        printf("%lld\n",sum);
    }


    return 0;
}