【LGR-158-Div.4】洛谷入门赛 #16G题

#include <iostream>
#include <iomanip>
using namespace std;
long double second(long i, long j, long k)
{
    long long a = 5 * (i) * (2 * i - 1) * (i - 1) / 6 + 3 * (i - 1) * i + i;
    long long b = (5 * j - 4) * j;
    long long c = k;
    return a + b + c;
}
int main()
{
    int T;
    cin >> T;
    while (T--)
    {
        int n, A, B, C, E, F, G;
        scanf("%d", &n);
        scanf("%d", &A);
        scanf("%d", &B);
        scanf("%d", &C);
        scanf("%d", &E);
        scanf("%d", &F);
        scanf("%d", &G);
        unsigned long long a = second(A, B, C);
        unsigned long long b = second(E, F, G);
        unsigned long long c = second(n, 0, 0);
        if (a < b)
        {
            cout << setprecision(0) << b - a << endl;
        }
        else
        {
            cout << setprecision(0) << c - a + b << endl;
        }
    }
}

除了样例全部WA，是不是a==b时计算错误？