HDU6128-Inverse of sum

参考这篇博客：https://blog.csdn.net/dormousenone/article/details/77340852

#include<bits/stdc++.h>
using namespace std;
typedef long long LL;
#define MAXN 100010
LL a[MAXN], n, p;

LL calc(){
    LL res = ;
    a[n] = -;
    , cnt = ;i <= n;++i){
        ])cnt++;
        else{
            res += LL(cnt - ) * cnt / ;
            cnt = ;
        }
    }
    return res;
}

LL qmult(LL x, LL y){
    LL res = ;
    if(x < y)swap(x, y);
    while(y){
        )res = (res + x) % p;
        x = (x << ) % p;
        y >>= ;
    }
    return res;
}

int main(){
    int T;
    scanf("%d", &T);
    while(T--){
        scanf("%I64d%I64d", &n, &p);
        ;i < n;++i)scanf("%I64d", a + i);
        ){
            , cnt2 = ;
            ;i < n;++i){
                )cnt1++;
                ) cnt2++;
            }
            LL ans = LL(cnt1 - ) * cnt1 /  + LL(cnt2 - ) * cnt2 / ;
            cout << ans << endl;
        }else{
            sort(a, a + n);
            LL ans = -calc();
            ;i < n;++i)a[i] = qmult(a[i], qmult(a[i], a[i]));
            sort(a, a + n);
            ans += calc();
            cout << ans << endl;
        }
    }
    ;
}