제출 #521044

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
521044		cig32	Mergers (JOI19_mergers)	C++17	0 / 100	414 ms	61560 KiB

mergers

#include "bits/stdc++.h"
#define int long long
using namespace std;
const int MAXN = 5e5 + 10;
vector<int> adj[MAXN];
vector<int> adj2[MAXN];
int s[MAXN];
int dsu[MAXN];
int set_of(int u) {
  if(dsu[u] == u) return u;
  return dsu[u] = set_of(dsu[u]);
}
void union_(int u, int v) {
  dsu[set_of(u)] = set_of(v);
}
map<pair<int, int>, bool> lit;
int cnt[MAXN], tot[MAXN];
int r = 0; // Number of colors that are in both sides
void dfs(int node, int prev) {
  if(r == 0 && prev != -1) {
    lit[{node, prev}] = lit[{prev, node}] = 1;
  }
  r -= (cnt[s[node]] == 0 || cnt[s[node]] == tot[s[node]] ? 0 : 1);
  cnt[s[node]]--;
  r += (cnt[s[node]] == 0 || cnt[s[node]] == tot[s[node]] ? 0 : 1);
  for(int x: adj[node]) {
    if(x != prev) {
      dfs(x, node);
    }
  }
  r -= (cnt[s[node]] == 0 || cnt[s[node]] == tot[s[node]] ? 0 : 1);
  cnt[s[node]]++;
  r += (cnt[s[node]] == 0 || cnt[s[node]] == tot[s[node]] ? 0 : 1);
}
int32_t main() {
  int n,k;cin >> n >> k;
  for(int i=1;i<n;i++) {
    int a,b;cin >> a >> b;
    adj[a].push_back(b);
    adj[b].push_back(a);
  }
  for(int i=1; i<=n; i++) cin >> s[i];
  for(int i=1; i<=n; i++) tot[s[i]]++, cnt[s[i]]++;
  for(int i=0; i<=n; i++) dsu[i] = i;
  dfs(1, -1);
  for(int i=1; i<=n; i++) {
    for(int x: adj[i]) {
      if(i < x) {
        if(!lit[{i, x}]) {
          union_(i, x);
        }
      }
    }
  }
  map<pair<int, int>, bool> mp;
  for(int i=1; i<=n; i++) {
    for(int x: adj[i]) {
      if(set_of(i) != set_of(x) && mp[{set_of(i), set_of(x)}] == 0) {
        mp[{set_of(i), set_of(x)}] = 1;
        mp[{set_of(x), set_of(i)}] = 1;
        adj2[set_of(i)].push_back(set_of(x));
        adj2[set_of(x)].push_back(set_of(i));
      }
    }
  }
  int s = 0;
  for(int i=1; i<=n; i++) {
    s += (adj2[i].size() == 1);
  }
  cout << (s + 1) / 2 << "\n";
}

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