Submission #1167928

#	Time	Username	Problem	Language	Result	Execution time	Memory
1167928		CrabCNH	Star triangles (IZhO11_triangle)	C++20	100 / 100	446 ms	23328 KiB

triangle

#include <bits/stdc++.h>

#define task   "BriantheCrab"

#define int    long long
#define pii    pair <int, int>
#define fi     first
#define se     second
#define szf    sizeof
#define sz(s)  (int)((s).size())

using namespace std;

template <class T> void mini (T &t, T f) {if (t > f) t = f;}
template <class T> void maxi (T &t, T f) {if (t < f) t = f;}

const int maxN = 1e5 + 5;
const int inf = 1e18 + 7;
const int mod = 1e9 + 7;

map <pii, int> mp;
map <int, int> t1, t2;

void solve () {
    int n;
    cin >> n;
    for (int i = 1; i <= n; i ++) {
        int x, y;
        cin >> x >> y;
        mp[{x, y}] ++;
    }
    for (auto [a, _] : mp) {
        auto [x, y] = a;
        t1[x] ++;
        t2[y] ++;
    }
    int res = 0;
    for (auto [a, _] : mp) {
        auto [x, y] = a;
        res += (t1[x] - 1) * (t2[y] - 1);
    }
    cout << res;
}

signed main () {
    cin.tie (nullptr) -> sync_with_stdio (false);
    if (fopen (task".inp", "r")) {
        freopen (task".inp", "r", stdin);
        freopen (task".out", "w", stdout);
    }
    int t = 1;
    //cin >> t;
    while (t --) {
        solve ();
    } 
    return 0;
}
// thfdgb

Compilation message (stderr)

triangle.cpp: In function 'int main()':
triangle.cpp:48:17: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   48 |         freopen (task".inp", "r", stdin);
      |         ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
triangle.cpp:49:17: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   49 |         freopen (task".out", "w", stdout);
      |         ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 100 / 100