Submission #309081

#	Time	Username	Problem	Language	Result	Execution time	Memory
309081		VROOM_VARUN	Mergers (JOI19_mergers)	C++14	0 / 100	191 ms	26608 KiB

mergers

/*
ID: varunra2
LANG: C++
TASK: mergers
*/

#include <bits/stdc++.h>
using namespace std;

#ifdef DEBUG
#include "lib/debug.h"
#define debug(...) cerr << "[" << #__VA_ARGS__ << "]:", debug_out(__VA_ARGS__)
#define debug_arr(...) \
  cerr << "[" << #__VA_ARGS__ << "]:", debug_arr(__VA_ARGS__)
#pragma GCC diagnostic ignored "-Wsign-compare"
//#pragma GCC diagnostic ignored "-Wunused-parameter"
//#pragma GCC diagnostic ignored "-Wunused-variable"
#else
#define debug(...) 42
#endif

#define EPS 1e-9
#define IN(A, B, C) assert(B <= A && A <= C)
#define INF (int)1e9
#define MEM(a, b) memset(a, (b), sizeof(a))
#define MOD 1000000007
#define MP make_pair
#define PB push_back
#define all(cont) cont.begin(), cont.end()
#define rall(cont) cont.end(), cont.begin()
#define x first
#define y second

const double PI = acos(-1.0);
typedef long long ll;
typedef long double ld;
typedef pair<int, int> PII;
typedef map<int, int> MPII;
typedef multiset<int> MSETI;
typedef set<int> SETI;
typedef set<string> SETS;
typedef vector<int> VI;
typedef vector<PII> VII;
typedef vector<VI> VVI;
typedef vector<string> VS;

#define rep(i, a, b) for (int i = a; i < (b); ++i)
#define trav(a, x) for (auto& a : x)
#define sz(x) (int)(x).size()
typedef pair<int, int> pii;
typedef vector<int> vi;
#pragma GCC diagnostic ignored "-Wsign-compare"
// util functions

void merge(MPII& a, MPII& b) {
  if (sz(a) < sz(b)) {
    swap(a, b);
  }
  trav(x, b) a[x.x] += x.y;
}

int n, k;

VI totcnt;
VI sub;
VVI adj;
VI state;
vector<MPII> cnt;
// int badcnt = 0;
VI bad;

void init() {
  adj.resize(n);
  cnt.resize(n);
  sub.resize(n);
  state.resize(n);
  totcnt.resize(n);
  bad.resize(n);
}

void dfs(int u, int v) {  // calc subsize/cnt
  sub[u] = 1;
  totcnt[state[u]]++;
  for (auto& x : adj[u]) {
    if (x == v) continue;
    dfs(x, u);
    sub[u] += sub[x];
  }
}

void dfscnt(int u, int v) {
  cnt[u][state[u]]++;
  for (auto& x : adj[u]) {
    if (x == v) continue;
    dfscnt(x, u);
    merge(cnt[u], cnt[x]);
  }
  // if we are dominating this subtree...
  if (cnt[u][state[u]] == totcnt[state[u]] and totcnt[state[u]] == sub[u]) {
    bad[state[u]] = 1;
  }

  if (v >= 0) {
    if (cnt[u][state[v]] == 0 and (n - sub[u]) == totcnt[state[v]]) {
      bad[state[v]] = 1;
    }
  }
}

int main() {
  // #ifndef ONLINE_JUDGE
  // freopen("mergers.in", "r", stdin);
  // freopen("mergers.out", "w", stdout);
  // #endif
  cin.sync_with_stdio(0);
  cin.tie(0);

  cin >> n >> k;

  if (k == 1) {
    cout << "0\n";
    return 0;
  }

  init();

  for (int i = 0; i < n - 1; i++) {
    int u, v;
    cin >> u >> v;
    u--, v--;
    adj[u].PB(v);
    adj[v].PB(u);
  }

  for (int i = 0; i < n; i++) {
    cin >> state[i];
    state[i]--;
  }

  dfs(0, -1);
  dfscnt(0, -1);

  cout << accumulate(all(bad), 1) / 2 << '\n';

  return 0;
}

• Subtask 1: 0 / 10
• Subtask 2: 0 / 24
• Subtask 3: 0 / 14
• Subtask 4: 0 / 22
• Subtask 5: 0 / 30