Submission #297520

#	Time	Username	Problem	Language	Result	Execution time	Memory
297520		fedoseevtimofey	Power Plant (JOI20_power)	C++14	100 / 100	280 ms	53380 KiB

power

#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>
#include <bitset>
#include <chrono>
 
using namespace std;
 
typedef long long ll;
 
int main() {
  ios_base::sync_with_stdio(false); cin.tie(0);
#ifdef LOCAL
  freopen("input.txt", "r", stdin);
#endif
  int n;
  cin >> n;
  vector <vector <int>> g(n);
  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);
  }
  vector <int> c(n);
  for (int i = 0; i < n; ++i) {
    char r;
    cin >> r;
    c[i] = r - '0';
  }
  vector <vector <int>> dp(n, vector <int> (2));
  function <void(int, int)> dfs = [&] (int u, int p) {
    vector <int> gs;
    for (auto v : g[u]) {
      if (v != p) {
        gs.push_back(v);
        dfs(v, u);
      }
    }
    if (c[u] == 0) {
      for (auto v : gs) {
        dp[u][1] += dp[v][1];
        dp[u][0] = max(dp[u][0], dp[v][0]);
      }
    } else {
      dp[u][0] = -1;
      dp[u][1] = -1;
      int mx = 0;
      for (auto v : gs) {
        dp[u][0] += dp[v][1]; 
        dp[u][1] += dp[v][1];
        mx = max(mx, dp[v][1]);
      } 
      dp[u][0] = max(dp[u][0], 1 + mx);
      dp[u][1] = max(dp[u][1], 1);
    }
  };
  dfs(0, -1);
  int ans = 0;
  for (int i = 0; i < n; ++i) ans = max(ans, max(dp[i][0], dp[i][1]));
  /*for (int i = 0; i < n; ++i) {
    cout << dp[i][0] << ' ' << dp[i][1] << endl;
  }*/
  cout << ans << '\n';
}

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