/* **************************************************************** **************************************************************** -> Coded by Stavros Chryselis -> Visit my github for more solved problems over multiple sites -> https://github.com/StavrosChryselis -> Feel free to email me at stavrikios@gmail.com **************************************************************** **************************************************************** */ #include #include #include #include using namespace std; int main() { int n; cin >> n; int a[n]; vector v1, v2; for(int i = 0; i < n; i++) cin >> a[i]; for(int i = 0; i < n; i++) for(int j = 0; j < n; j++) for(int k = 0; k < n; k++) v1.push_back(a[i]*a[j]+a[k]); for(int i = 0; i < n; i++) for(int j = 0; j < n; j++) for(int k = 0; k < n; k++) { if(a[i]) v2.push_back(a[i]*(a[j]+a[k])); } sort(v1.begin(), v1.end()); sort(v2.begin(), v2.end()); long long count = 0; pair::iterator, vector::iterator> bounds; for(vector::iterator it = v1.begin(); it != v1.end(); it++) { bounds = equal_range(v2.begin(), v2.end(), *it); count += bounds.second-bounds.first; } cout << count << endl; return 0; }