Submission #1092040

#	Time	Username	Problem	Language	Result	Execution time	Memory
1092040		juicy	Star triangles (IZhO11_triangle)	C++17	100 / 100	229 ms	26544 KiB

triangle

#include <bits/stdc++.h>

using namespace std;

#ifdef LOCAL
#include "debug.h"
#else
#define debug(...) 42
#endif

int main() {
  ios::sync_with_stdio(false); cin.tie(nullptr);

  int n; cin >> n;
  vector<array<array<int, 2>, 2>> cnt(n);
  array<map<int, vector<array<int, 2>>>, 2> mp;
  for (int i = 0; i < n; ++i) {
    int x, y; cin >> x >> y;
    mp[0][x].push_back({y, i});
    mp[1][y].push_back({x, i});
  }
  for (auto it : {0, 1}) {
    for (auto [x, a] : mp[it]) {
      sort(a.begin(), a.end());
      for (int i = 0; i < a.size(); ) {
        int j = i;
        while (j < a.size() && a[j][0] == a[i][0]) {
          ++j;
        }
        array<int, 2> v = {i, int(a.size()) - j};
        while (i < j) {
          cnt[a[i++][1]][it] = v;
        }
      }
    }
  }
  long long res = 0;
  for (int i = 0; i < n; ++i) {
    for (int x = 0; x < 2; ++x) {
      for (int y = 0; y < 2; ++y) {
        res += (long long) cnt[i][0][x] * cnt[i][1][y];
      }
    }
  }
  cout << res;
  return 0;
}

Compilation message (stderr)

triangle.cpp: In function 'int main()':
triangle.cpp:25:25: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::array<int, 2> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   25 |       for (int i = 0; i < a.size(); ) {
      |                       ~~^~~~~~~~~~
triangle.cpp:27:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::array<int, 2> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   27 |         while (j < a.size() && a[j][0] == a[i][0]) {
      |                ~~^~~~~~~~~~

• Subtask 1: 100 / 100