Bignum - Optimization (LMH)

#define taskname "BALANCE"
#include <iostream>
#include <cstdlib>
#include <cstdio>
#include <algorithm>
#include <array>
#include <iomanip>
using namespace std;
using lli = long long;
using ld = long double;
const int maxN = 100;
const int maxM = maxN * (maxN + 1) / 2;
const lli Radix = 1e18;
const int gd = 18;
const int nd = 3;


int n, m, k;

struct TNumber
{
    array<lli, nd> d; //d[0] + d[1] * Radix + d[2] * Radix ^ 2.
    TNumber& operator = (lli x)
    {
        fill(d.begin(), d.end(), 0);
        d[0] = x;
        return *this;
    }
    TNumber operator + (const TNumber& other) const
    {
        TNumber res;
        lli carry = 0LL;
        for (int i = 0; i < nd; ++i)
        {
            carry += d[i] + other.d[i];
            res.d[i] = carry % Radix;
            carry /= Radix;
        }
        return res;
    }
    void Print() const
    {
        int i = nd - 1;
        while (i > 0 && d[i] == 0) --i;
        cout << d[i];
        for (--i; i >= 0; --i)
            cout << setw(gd) << setfill('0') << d[i];
    }
};


TNumber f[maxM + 1], g[maxM + 1];

void ReadInput()
{
    cin >> n >> m;
    k = n * (n + 1) / 2;
}

void Solve()
{
    f[0] = 1;
    for (int y = 1; y <= k; ++y)
        f[y] = 0;
    for (int x = 1; x <= n; ++x)
    {
        for (int y = 0; y <= k; ++y)
        {
            g[y] = f[y] + f[abs(x - y)];
            if (x + y <= k) g[y] = g[y] + f[x + y];
        }
        swap(f, g);
    }
    f[m].Print();
}

int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    //freopen(taskname".INP", "r", stdin);
    //freopen(taskname".OUT", "w", stdout);
    ReadInput();
    Solve();
}