Cod sursa(job #2216849)
Utilizator | Data | 28 iunie 2018 08:49:26 | |
---|---|---|---|
Problema | Oite | Scor | 100 |
Compilator | cpp | Status | done |
Runda | Arhiva de probleme | Marime | 0.56 kb |
#include <fstream>
#include <algorithm>
#include <unordered_map>
using namespace std;
ifstream cin ("oite.in");
ofstream cout ("oite.out");
const int NMAX = 1024;
int n, l;
long long sol;
int v[1 + NMAX];
unordered_map <int, int> f;
int main() {
cin >> n >> l;
for(int i = 1; i <= n; i++)
cin >> v[i];
sort(v + 1, v + n + 1);
for(int i = 1; i <= n; i++) {
for(int j = i + 1; j <= n; j++)
sol += f[l - (v[i] + v[j])];
for(int j = i - 1; j >= 1; j--)
f[v[i] + v[j]]++;
}
cout << sol;
return 0;
}