Submission #212162

#	Time	Username	Problem	Language	Result	Execution time	Memory
212162		achvanov	Making Friends on Joitter is Fun (JOI20_joitter2)	C++17	0 / 100	10 ms	9728 KiB

joitter2

#include <bits/stdc++.h>

using namespace std;

const int N = 1e5 + 10;
int n, m;
long long ans;
int p[N];
long long sz[N];
set<int> f[N], g[N];

int get(int v) {
  return (v == p[v] ? v : p[v] = get(p[v]));
}

void unite(int u, int v) {
  u = get(u), v = get(v);
  if (u == v) {
    return;
  }
  if (f[u].size() + g[u].size() < f[v].size() + g[v].size()) {
    swap(u, v);
  }
  ans -= f[u].size() * sz[u] - sz[u];
  ans -= f[v].size() * sz[v] - sz[v];
  for (int x : f[v]) {
    f[u].insert(x);
  }
  for (int x : g[v]) {
    g[u].insert(x);
  }
  sz[u] += sz[v];
  p[v] = u;
  ans += f[u].size() * sz[u] - sz[u];
}

void connect(int u, int v) {
  int uu = get(u), vv = get(v);
  if (uu == vv) {
    return;
  }
  if (f[vv].count(u)) {
    return;
  }
  if (g[uu].count(vv)) {
    unite(u, v);
  } else {
    ans += sz[vv];
    f[vv].insert(u);
    g[vv].insert(uu);
  }
}

int main() {
  ios::sync_with_stdio(0);
  cin.tie(0), cout.tie(0);

  cin >> n >> m;
  for (int i = 0; i < n; ++i) {
    p[i] = i;
    f[i].insert(i);
    sz[i] = 1;
  }
  while (m--) {
    int u, v;
    cin >> u >> v;
    --u, --v;
    connect(u, v);
    cout << ans << '\n';
  }

  return 0;
}

• Subtask 1: 0 / 1
• Subtask 2: 0 / 16
• Subtask 3: 0 / 83