Submission #518676

#	Time	Username	Problem	Language	Result	Execution time	Memory
518676		cig32	Power Plant (JOI20_power)	C++17	0 / 100	7 ms	7372 KiB

power

#pragma GCC optimize("Ofast")
#include <bits/stdc++.h>
using namespace std;
mt19937_64 rng((int)std::chrono::steady_clock::now().time_since_epoch().count());
const int MAXN = 3e5 + 10;
const int MOD = 1e9 + 7;
#define int long long

vector<int> adj[MAXN];
char c[MAXN];
int dpf(int node, int prev) {
  int sum = 0;
  for(int x: adj[node]) {
    if(x != prev) sum += dpf(x, node);
  }
  if(c[node] == '0') {
    return sum;
  }
  else {
    return max(1ll, sum - 1);
  }
}
int sz[MAXN];
bool cis[MAXN];
void dfs(int node) {
  cis[node] = 1;
  for(int x: adj[node]) {
    if(!cis[x]) {
      sz[x]--;
      if(sz[x] == 1) {
        dfs(x);
      }
    }
  }
}
void solve(int tc) {
  int N;
  cin >> N;
  for(int i=1; i<N; i++) {
    int a, b;
    cin >> a >> b;
    adj[a].push_back(b);
    adj[b].push_back(a);
  }
  if(N == 1) {
    cout << "1\n"; return;
  }
  for(int i=1; i<=N; i++) cin >> c[i];
  for(int i=1; i<=N; i++) sz[i] = adj[i].size();
  for(int i=1; i<=N; i++) {
    if(c[i] == '0' && sz[i] == 1 && !cis[i]) {
      dfs(i);
    }
  }
  int cnt = 0;
  for(int i=1; i<=N; i++) cnt += (c[i] == '0' && !cis[i]);
  if(cnt == 0) {
    int ans = 0;
    for(int i=1; i<=N; i++) ans += (c[i] == '1');
    ans = min(ans, 2ll);
    for(int i=1; i<=N; i++) ans = max(ans, (int)adj[i].size() - 1);
    cout << ans << "\n"; return;
  }
  for(int i=1; i<=N; i++) {
    if(c[i] == '0' && !cis[i]) {
      cout << dpf(i, -1) << "\n";
      return;
    }
  }
}

int32_t main(){
  ios::sync_with_stdio(0); cin.tie(0);
  int t = 1; //cin >> t;
  for(int i=1; i<=t; i++) solve(i);
} 

• Subtask 1: 0 / 6
• Subtask 2: 0 / 41
• Subtask 3: 0 / 53