Submission #220188

#	Time	Username	Problem	Language	Result	Execution time	Memory
220188		fedoseevtimofey	Capital City (JOI20_capital_city)	C++14	1 / 100	72 ms	2296 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];
int c[N];
bool bad[N][N];

int par[N], cnt[N];

int get(int a) {
  return (a == par[a] ? a : par[a] = get(par[a]));
}

void join(int a, int b) {
  a = get(a);
  b = get(b);
  if (a != b) {
    par[a] = b;
    cnt[b] += cnt[a];
    ++cnt[b];
  }
}

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();
}

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) {
    par[i] = i;
  }
  for (int i = 0; i < k; ++i) {
    for (int j = i + 1; j < k; ++j) {
      if (bad[i][j] && bad[j][i]) {
        join(i, j);
      }
    }
  }
  vector <int> ok(k, true);
  for (int i = 0; i < k; ++i) {
    for (int j = 0; j < k; ++j) {
      if (bad[i][j] && get(i) != get(j)) {
        ok[get(i)] = false;
      }
    }
  }
  int ans = n;
  bool fnd = false;
  for (int i = 0; i < k; ++i) {
    if (ok[get(i)]) {
      ans = min(ans, cnt[get(i)]);
      fnd = true;
    }
  }
  assert(fnd);
  cout << ans << '\n';
}

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