tamgiac.cpp

#include<iostream>
#include<cstdlib>
#include<vector>
#include<algorithm>
#include<unordered_map>

#define long long long
#define nln '\n'

using namespace std;

int main()
{
    cin.tie(0)->sync_with_stdio(0);
    cout.tie(0)->sync_with_stdio(0);
    freopen("tamgiac.inp", "r", stdin);
    //freopen("tamgiac.out", "w", stdout);
    long n;
    cin >> n;
    vector<long> a(n), b;
    unordered_map<long, long> cnt;
    for (auto &i : a)
        cin >> i, b.push_back(i*i), ++cnt[b.back()];;
    // Process
    sort(a.begin(), a.end());
    sort(b.begin(), b.end());
    long obt = 0, tag = 0, rig = 0;
    for (long i = 1; i < n-1; ++i)
        for (long j = 0; j < i; ++j)
        {
            // Tim nhung bo ba la tam giac
            long pst = prev(lower_bound(a.begin()+i+1, a.end(), a[i]+a[j]))-a.begin();
            if (pst == -1) continue;
            tag += pst-i;
            // Tim nhung bo ba la tam giac vuong
            rig += cnt[b[i]+b[j]];
            long pst2 = upper_bound(b.begin()+i+1, b.end(), b[i]+b[j])-b.begin();
            // Tim nhung bo ba la tam gia tu
            if (pst2 > pst) continue;
            obt += pst-pst2+1;
        }
    cout << tag-obt-rig << ' ' << rig << ' ' << obt << nln;
    return 0;
}