Submission #220191

#	Time	Username	Problem	Language	Result	Execution time	Memory
220191		fedoseevtimofey	Capital City (JOI20_capital_city)	C++14	11 / 100	524 ms	8952 KiB

capital_city

#include <iostream>
#include <string>
#include <vector>
#include <queue>
#include <deque>
#include <stack>
#include <set>
#include <map>
#include <unordered_map>
#include <unordered_set>
#include <cstring>
#include <cmath>
#include <cstdlib>
#include <algorithm>
#include <random>
#include <iomanip>
#include <functional>
#include <cassert>

using namespace std;

typedef long long ll;

const int N = 3000 + 7;

vector <int> g[N];
vector <int> gr[N];
vector <int> rg[N];

int c[N];
bool bad[N][N];

vector <int> path;

void dfs(int u, int p = -1) {
  path.push_back(u); 
  if (c[path.back()] == c[path.front()]) {
    for (int v : path) {
      if (c[v] != c[u]) {
        bad[c[u]][c[v]] = 1;
      }
    }
  }
  for (auto v : g[u]) {
    if (v != p) {
      dfs(v, u);
    }
  }
  path.pop_back();
}

vector <int> t;
bool used[N];
int cmp[N];
bool ok[N];
int sz[N];

void get_topsort(int u) {
  used[u] = true;
  for (auto v : gr[u]) {
    if (!used[v]) {
      get_topsort(v);
    }
  }
  t.push_back(u);
}

int cnt = 0;

void jhfs(int u) {
  used[u] = true;
  cmp[u] = cnt;
  ++sz[cnt];
  for (auto v : rg[u]) {
    if (!used[v]) {
      jhfs(v);
    }
  }
}

int main() {
  ios_base::sync_with_stdio(false); cin.tie(0);
#ifdef LOCAL
  freopen("input.txt", "r", stdin);
#endif
  int n, k;
  cin >> n >> k;
  for (int i = 0; i + 1 < n; ++i) {
    int u, v;
    cin >> u >> v;
    --u, --v;
    g[u].push_back(v);
    g[v].push_back(u);
  }
  for (int i = 0; i < n; ++i) {
    cin >> c[i];
    --c[i];
  }
  for (int i = 0; i < n; ++i) {
    dfs(i, -1);
  }
  for (int i = 0; i < k; ++i) {
    for (int j = 0; j < k; ++j) {
      if (bad[i][j]) {
        gr[i].push_back(j);
        rg[j].push_back(i);
      }
    }
  }
  for (int i = 0; i < k; ++i) {
    if (!used[i]) {
      get_topsort(i);
    }
  }
  reverse(t.begin(), t.end());
  fill(used, used + k, false);   
  for (int u : t) {
    if (!used[u]) {
      jhfs(u);
      ++cnt;
    }
  }
  fill(ok, ok + cnt, true);
  for (int i = 0; i < k; ++i) {
    for (int j : gr[i]) {
      if (cmp[i] != cmp[j]) {
        ok[cmp[i]] = false;
      }
    }
  }
  int ans = n;
  for (int i = 0; i < cnt; ++i) {
    if (ok[i]) ans = min(ans, sz[i]);
  }
  cout << ans - 1 << '\n';
}

• Subtask 1: 1 / 1
• Subtask 2: 10 / 10
• Subtask 3: 0 / 30
• Subtask 4: 0 / 59