Submission #773026

#	Time	Username	Problem	Language	Result	Execution time	Memory
773026		Sam_a17	Power Plant (JOI20_power)	C++17	6 / 100	13 ms	5276 KiB

power

#define _CRT_SECURE_NO_WARNINGS
#include <bits/stdc++.h>
//#include "temp.cpp"
#include <cstdio>
using namespace std;
 
#ifndef ONLINE_JUDGE
#define dbg(x) cerr << #x <<" "; print(x); cerr << endl;
#else
#define dbg(x)
#endif
 
#define sz(x) (int)x.size()
#define len(x) (int)x.length()
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define clr(x) (x).clear()
#define uniq(x) x.resize(unique(all(x)) - x.begin());
#define blt __builtin_popcount
 
#define pb push_back
#define popf pop_front
#define popb pop_back
#define ld long double
#define ll long long
 
void print(long long t) {cerr << t;}
void print(int t) {cerr << t;}
void print(string t) {cerr << t;}
void print(char t) {cerr << t;}
void print(double t) {cerr << t;}
void print(long double t) {cerr << t;}
void print(unsigned long long t) {cerr << t;}
 
#include <ext/pb_ds/assoc_container.hpp>
using namespace __gnu_pbds;
#define nl '\n'
 
// Indexed Set  
template <class T> using Tree = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
 
template <class T, class V> void print(pair <T, V> p);
template <class T> void print(vector <T> v);
template <class T> void print(set <T> v);
template <class T, class V> void print(map <T, V> v);
template <class T> void print(multiset <T> v);
template <class T, class V> void print(T v[],V n) {cerr << "["; for(int i = 0; i < n; i++) {print(v[i]); cerr << " "; } cerr << "]";}
template <class T, class V> void print(pair <T, V> p) {cerr << "{"; print(p.first); cerr << ","; print(p.second); cerr << "}";}
template <class T> void print(vector <T> v) {cerr << "[ "; for (T i : v) {print(i); cerr << " ";} cerr << "]";}
// template <class T> void print(vector <T> v) {cerr << "[ "; for (T i : v) {print(i); cerr << " ";} cerr << "]";}
template <class T> void print(set <T> v) {cerr << "[ "; for (T i : v) {print(i); cerr << " ";} cerr << "]";}
template <class T> void print(multiset <T> v) {cerr << "[ "; for (T i : v) {print(i); cerr << " ";} cerr << "]";}
template <class T> void print(Tree <T> v) {cerr << "[ "; for (T i : v) {print(i); cerr << " ";} cerr << "]";}
template <class T, class V> void print(map <T, V> v) {cerr << "[ "; for (auto i : v) {print(i); cerr << " ";} cerr << "]";}
template <class T> void print(deque <T> v) {cerr << "[ "; for (T i : v) {print(i); cerr << " ";} cerr << "]";}
 
 
// for random generations
// mt19937 myrand(chrono::steady_clock::now().time_since_epoch().count());
mt19937 myrand(313);
 
// for grid problems
int dx[8] = {-1,0,1,0,1,-1,1,-1};
int dy[8] = {0,1,0,-1,1,1,-1,-1};
 
// lowest / (1 << 17) >= 1e5 / (1 << 18) >= 2e5 / (1 << 21) >= 1e6
void fastIO() {
  ios_base::sync_with_stdio(false);
  cin.tie(nullptr); cout.tie(nullptr);
}
// file in/out
void setIO(string str = "") {
  fastIO();
 
  // if(str == "input") {
    // freopen("input.txt", "r", stdin);
    // freopen("output.txt", "w", stdout);
  // } else if(str != "") {
    // freopen((str + ".in").c_str(), "r", stdin);
    // freopen((str + ".out").c_str(), "w", stdout);
  // }
}
 
const int N = 2e5 + 10;
vector<int> adj[N];
int n, dp[N];
bool is_bomb[N];
  int answ = 0;
 
void dfs(int node, int parent) {
  if(parent) {
    if(is_bomb[node]) {
      dp[node] = 1;
    } else {
      dp[node] = 0;
    }
  } else {
    dp[node] = 0;
  }
 
  for(auto i: adj[node]) {
    if(i == parent) continue;
    dfs(i, node);
  }
 
  int is_black = 0, ans = 0;
  for(auto i: adj[node]) {
    if(i == parent) continue;
    if(dp[i] > 0) {
      is_black++;
    }
    ans += max(0, dp[i]);
  }
 
  if(is_black) {
    ans -= dp[node];
  }
  
  if(!parent) {
    if(is_black >= 2) {
      answ = max(answ, ans - is_bomb[node]);
    } else {
      answ = max(answ, ans + is_bomb[node]);
    }
  } else {
    dp[node] = max(dp[node], ans);
  }
}
 
void solve_() {
  cin >> n;
 
  for(int i = 1; i <= n - 1; i++) {
    int a, b; cin >> a >> b;
    adj[a].push_back(b);
    adj[b].push_back(a);
  }
 
  string s; cin >> s;
  vector<int> can;
  for(int i = 0; i < n; i++) {
    if(s[i] == '1') {
      can.push_back(i + 1);
      is_bomb[i + 1] = true;
    } 
  }

  vector<bool> vis(n + 1);
  for(int i = 0; i < min(sz(can), 300); i++) {
    int rnd = myrand() % sz(can);
    while(vis[rnd]) {
      rnd = myrand() % sz(can);
    }
    dfs(can[rnd], 0);
    vis[rnd] = true;
  }
 
  cout << answ << '\n';
}
 
int main() {
  setIO();
 
  auto solve = [&](int test_case)-> void {
    for(int i = 1; i <= test_case; i++) {
      solve_();
    }
  };
 
  int test_cases = 1;
  // cin >> test_cases;
  solve(test_cases);
 
  return 0;
}

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