Submission #963281

#	Time	Username	Problem	Language	Result	Execution time	Memory
963281		Soumya1	Making Friends on Joitter is Fun (JOI20_joitter2)	C++17	100 / 100	969 ms	81832 KiB

joitter2

#include <bits/stdc++.h>
using namespace std;
const int mxN = 1e5 + 5;
int sz[mxN], par[mxN];
queue<pair<int, int>> q;
set<int> outc[mxN], inc[mxN], inn[mxN];
set<pair<int, int>> outn[mxN];
long long ans;
int find(int u) {
  return (u == par[u] ? u : find(par[u]));
}
long long contrib(int a) {
  return 1LL * sz[a] * (sz[a] + inn[a].size() - 1);
}
void merge(int a, int b) {
  int aa = find(a), bb = find(b);
  if (aa == bb) return;
  if (inn[bb].find(a) != inn[bb].end()) return;
  if (outc[bb].find(aa) == outc[bb].end()) {
    ans -= contrib(bb);
    inc[bb].insert(aa);
    outc[aa].insert(bb);
    inn[bb].insert(a);
    outn[aa].insert({a, bb});
    ans += contrib(bb);
    return;
  }
  ans -= contrib(aa) + contrib(bb);
  if (sz[aa] > sz[bb]) swap(aa, bb), swap(a, b);
  outc[bb].erase(aa);
  inc[aa].erase(bb);
  for (int x : outc[aa]) {
    inc[x].erase(aa);
  }
  for (int x : inc[aa]) {
    outc[x].erase(aa);
  }
  outc[aa].clear(), inc[aa].clear();
  for (auto x : inn[aa]) {
    q.push({x, bb});
    outn[find(x)].erase({x, aa});
  }
  for (auto [x, y] : outn[aa]) {
    q.push({x, y});
    if (y != bb) ans -= contrib(y);
    inn[y].erase(x);
    if (y != bb) ans += contrib(y);
  }
  inn[aa].clear(), outn[aa].clear();
  par[aa] = bb;
  sz[bb] += sz[aa];
  ans += contrib(bb);
}
void testCase() {
  int n, m;
  cin >> n >> m;
  for (int i = 1; i <= n; i++) {
    sz[i] = 1, par[i] = i;
  }
  while (m--) {
    int a, b;
    cin >> a >> b;
    q.push({a, b});
    while (!q.empty()) {
      auto [x, y] = q.front();
      q.pop();
      merge(x, y);
    }
    cout << ans << "\n";
  }
}
int main() {
  ios::sync_with_stdio(false);
  cin.tie(nullptr);
  testCase();
  return 0;
}

• Subtask 1: 1 / 1
• Subtask 2: 16 / 16
• Subtask 3: 83 / 83