Cod sursa(job #2587082)

Utilizator AlexandruGabrielAliciuc Alexandru AlexandruGabriel Data 21 martie 2020 23:43:56
Problema Oite Scor 70
Compilator cpp-64 Status done
Runda Arhiva de probleme Marime 1.33 kb
#include <bits/stdc++.h>

using namespace std;

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

const int N = 1030, mod = 666013;
int n, a[N], ans, m;
vector < pair <int, int> > H[mod + 1];
unordered_map <int, bool> M;

void Insert(int val)
{
    int key = val % mod;

    for (unsigned ind = 0; ind < H[key].size(); ind++)
    {
        if (val == H[key][ind].first)
        {
            H[key][ind].second++;
            return;
        }
    }

}

void findHash(int val)
{
    int key = val % mod;

    for (unsigned ind = 0; ind < H[key].size(); ind++)
    {
        if (val == H[key][ind].first)
            ans += H[key][ind].second;
    }
}

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++)
             if (a[i] + a[j] <= m)
                findHash(m - a[i] - a[j]);

        for (int j = 1; j < i; j++)
            if (a[i] + a[j] <= m)
            {
                if (!M[a[i] + a[j]])
                {
                    M[a[i] + a[j]] = 1;
                    H[(a[i] + a[j]) % mod].push_back(make_pair(a[i] + a[j], 1));
                }
                else
                    Insert(a[i] + a[j]);
            }
    }

    fout << ans;
    return 0;
}