Cod sursa(job #2587029)

Utilizator AlexandruGabrielAliciuc Alexandru AlexandruGabriel Data 21 martie 2020 21:56:02
Problema Oite Scor 60
Compilator cpp-64 Status done
Runda Arhiva de probleme Marime 0.97 kb
#include <bits/stdc++.h>

using namespace std;

ifstream fin ("oite.in");
ofstream fout ("oite.out");

const int N = 1030, mod = 1000003;
int n, a[N], ans, m;
vector < tuple<int, int> > H[mod + 1];

void findHash(int val, int j)
{
    if (val < 0)
        return;

    int key = val % mod;

    for (int ind = H[key].size() - 1; ind >= 0; ind--)
    {
        int x = get<0>(H[key][ind]);
        int k = get<1>(H[key][ind]);

        if (k > j)
        {
            if (x == val)
                ans++;
        }
        else
            return;
    }

}

int main()
{
    fin >> n >> m;
    for (int i = 1; i <= n; i++)
        fin >> a[i];

    for (int i = 1; i < n; i++)
        for (int j = i + 1; j <= n; j++)
            H[(a[i] + a[j]) % mod].push_back(make_tuple(a[i] + a[j], i));

    for (int i = 1; i < n; i++)
        for (int j = i + 1; j <= n; j++)
            findHash(m - (a[i] + a[j]), j);

    fout << ans;
    return 0;
}