Submission #976260

#	Time	Username	Problem	Language	Result	Execution time	Memory
976260		vjudge1	Star triangles (IZhO11_triangle)	C++17	100 / 100	250 ms	12628 KiB

triangle

#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define lld double
#define int ll
#define usaco(fname) freopen(#fname ".in","r",stdin);freopen(#fname ".out","w",stdout);
template<typename A, typename B> ostream& operator<<(ostream &os, const pair<A, B> &p) { return os << '(' << p.first << ", " << p.second << ')'; }
template<typename T_container, typename T = typename enable_if<!is_same<T_container, string>::value, typename T_container::value_type>::type> ostream& operator<<(ostream &os, const T_container &v) { os << '{'; string sep; for (const T &x : v) os << sep << x, sep = ", "; return os << '}'; }
// const ll INF = 1e18;
const int INF = 1e9;
const int mod = 1e9+7;
const lld PI = acos(-1.0);
int di[] = {1, -1, 0, 0, 1, 1, -1, -1};
int dj[] = {0, 0, 1, -1, 1, -1, 1, -1};
#define debug(x) cout << #x << ": " << x << endl;
#define add(a, b) a += b, a %= mod
#define mul(a, b) ((a % mod) * (b % mod)) % mod
#define all(x) x.begin(),x.end()

void solve() {
  int n;cin>>n;

  map<int, int> mpX, mpY;
  // x, y
  vector<pair<int, int>> points(n);
  for (int i = 0; i < n; i++) {
    cin >> points[i].first >> points[i].second;
    mpX[points[i].first]++;
    mpY[points[i].second]++;
  }

  int ans = 0;
  for (auto [x, y] : points) {
    ans += (mpX[x] - 1) * (mpY[y] - 1);
    // mpX[x]--;mpY[y]--;
  }

  cout << ans << endl;
}

int32_t main() {
  ios_base::sync_with_stdio(0);cin.tie(0);
  int t=1;
  while(t--) solve();

  return 0;
}

• Subtask 1: 100 / 100