Submission #621030

#	Time	Username	Problem	Language	Result	Execution time	Memory
621030		Sam_a17	Keys (IOI21_keys)	C++17	100 / 100	1154 ms	67336 KiB

keys

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

#define sz(x) (int)x.size()
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define uniq(x) x.resize(unique(all(x)) - x.begin());
#define dbg(x) cout  << #x << " " << x << endl;
#define ll long long
#define ld long double

mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

template<typename T>
void pr(vector<T>& a) {
  for(auto i: a) {
    cout << i << " ";
  }
  cout << endl;
}
void pr(vector<pair<int, int>>& a) {
  for(auto i: a) {
    cout << "{" << i.first << "," << i.second << "}" << " ";
  }
  cout << endl;
}

void pr(vector<pair<pair<int, int>, int>>& a) {
  for(auto i: a) {
    cout << "{ {" << i.first.first << "," << i.first.second << "}" << ", " << i.second << "} ";
  }
  cout << endl;
}

const int N = 4e5 + 10, inf = 1e9;
vector<pair<int, int>> adj[N];
vector<int> color[N];
bool finished[N], vis[N];
int n, m, answ[N], have_color[N];
int color_node[N];

int bfs(int node) {
  int count = 1;
  queue<int> q; vis[node] = true;
  vector<int> path{node}, colors;
  q.push(node); 

  while(!q.empty()) {
    auto u = q.front();
    q.pop();

    if(!have_color[color_node[u]]) {
      have_color[color_node[u]] = true;
      colors.push_back(color_node[u]);

      for(auto i: color[color_node[u]]) {
        if(finished[i]) {
          {
            for(auto j: path) {
              have_color[color_node[j]] = false;
              vis[j] = false;
            }
            for(auto j: colors) {
              color[j].clear();
            }
          }
          return inf;
        }

        if(!vis[i]) {
          vis[i] = true;
          count++, path.push_back(i);
          q.push(i);
        }
      } color[color_node[u]].clear();
    }

    for(auto i: adj[u]) {
      if(vis[i.first]) continue;
      
      if(!have_color[i.second]) {
        colors.push_back(i.second); 
        color[i.second].push_back(i.first);
        continue;
      }

      if(finished[i.first]) {
        {
          for(auto j: path) {
            have_color[color_node[j]] = false;
            vis[j] = false;
          }
          for(auto j: colors) {
            color[j].clear();
          }
        }
        return inf;
      }

      count++, path.push_back(i.first);
      vis[i.first] = true;
      q.push(i.first);
    }
  }

  for(auto j: path) answ[j] = min(answ[j], count);
  {
    for(auto j: path) {
      vis[j] = false;
    }
    for(auto j: colors) {
      have_color[j] = false;
      color[j].clear();
    }
  }
  return count;
}

vector<int> find_reachable(vector<int> r, vector<int> u, vector<int> v, vector<int> c) {
  n = sz(r), m = sz(u);

  vector<int> seq;
  for(int i = 0; i < m; i++) {
    adj[u[i]].push_back({v[i], c[i]});
    adj[v[i]].push_back({u[i], c[i]});
    seq.push_back(u[i]);
    seq.push_back(v[i]);
  }

  for(int i = 0; i < n; i++) {
    color_node[i] = r[i];
    answ[i] = inf;
  }

  shuffle(all(seq), rng);
  // pr(seq);
  for(auto i: seq) {
    if(!finished[i]) {
      int pat = bfs(i);
      answ[i] = min(answ[i], pat);
      finished[i] = true;
    }
  }

  for(int i = 0; i < n; i++) {
    if(!finished[i]) {
      int pat = bfs(i);
      answ[i] = min(answ[i], pat);
      finished[i] = true;
    }
  }

  int mini = inf;
  for(int i = 0; i < n; i++) {
    mini = min(mini, answ[i]);
  }

  vector<int> ans(n);
  for(int i = 0; i < n; i++) {
    if(answ[i] == mini) {
      ans[i] = 1;
    } else {
      ans[i] = 0;
    }
  }

  return ans;
}

• Subtask 1: 9 / 9
• Subtask 2: 11 / 11
• Subtask 3: 17 / 17
• Subtask 4: 30 / 30
• Subtask 5: 33 / 33