Submission #721133

#	Time	Username	Problem	Language	Result	Execution time	Memory
721133		Jarif_Rahman	Keys (IOI21_keys)	C++17	37 / 100	3060 ms	43104 KiB

keys

#include "keys.h"
#include <bits/stdc++.h>
#define pb push_back
#define f first
#define sc second
using namespace std;
typedef long long int ll;
typedef string str;

int n, m;
vector<int> r;
vector<vector<pair<int, int>>> graph;
vector<bool> candidate;

vector<vector<int>> waiting_list;
vector<bool> has_key;
vector<bool> bl;
void reduce_candidates(int s){
    vector<int> has_key_v, waiting_list_v, reachable;

    has_key[r[s]] = 1;
    has_key_v.pb(r[s]);

    queue<int> Q;
    Q.push(s);

    while(!Q.empty()){
        int nd = Q.front(); Q.pop();
        if(bl[nd]) continue;
        bl[nd] = 1;
        reachable.pb(nd);
        if(candidate[nd] && nd != s){
            candidate[s] = 0;
            break;
        }
        if(!has_key[r[nd]]){
            for(int x: waiting_list[r[nd]]) if(!bl[x]) Q.push(x);
            waiting_list[r[nd]].clear();
            has_key[r[nd]] = 1;
            has_key_v.pb(r[nd]);
        }
        for(auto [x, c]: graph[nd]) if(!bl[x]){
            if(has_key[c]) Q.push(x);
            else{
                waiting_list[c].pb(x);
                waiting_list_v.pb(c);
            }
        }
    }

    for(int x: has_key_v) has_key[x] = 0;
    for(int x: waiting_list_v) waiting_list[x].clear();
    for(int x: reachable) bl[x] = 0;
}

int P;
vector<int> ans, p;
void bfs(int s){
    vector<int> has_key_v, waiting_list_v, reachable;

    has_key[r[s]] = 1;
    has_key_v.pb(r[s]);

    queue<int> Q;
    Q.push(s);

    while(!Q.empty()){
        int nd = Q.front(); Q.pop();
        if(bl[nd]) continue;
        bl[nd] = 1;
        reachable.pb(nd);
        if(!has_key[r[nd]]){
            for(int x: waiting_list[r[nd]]) if(!bl[x]) Q.push(x);
            waiting_list[r[nd]].clear();
            has_key[r[nd]] = 1;
            has_key_v.pb(r[nd]);
        }
        for(auto [x, c]: graph[nd]) if(!bl[x]){
            if(has_key[c]) Q.push(x);
            else{
                waiting_list[c].pb(x);
                waiting_list_v.pb(c);
            }
        }
    }

    for(int x: has_key_v) has_key[x] = 0;
    for(int x: waiting_list_v) waiting_list[x].clear();
    for(int x: reachable) bl[x] = 0;

    if(reachable.size() < P){
        P = reachable.size();
        for(int x: p) ans[x] = 0;
        p = reachable;
        for(int x: reachable) ans[x] = 1;
    }
    else if(reachable.size() == P){
        p.insert(p.begin(), reachable.begin(), reachable.end());
        for(int x: reachable) ans[x] = 1;
    }
}

vector<int> find_reachable(vector<int> _r, vector<int> U, vector<int> V, vector<int> C){
    swap(r, _r);
    n = r.size(), m = U.size();
    graph.resize(n);
    candidate.assign(n, 1);
    has_key.assign(n, 0);
    bl.assign(n, 0);
    waiting_list.resize(n);
    ans.resize(n);
    P = n;

    for(int i = 0; i < m; i++){
        graph[U[i]].pb({V[i], C[i]});
        graph[V[i]].pb({U[i], C[i]});
    }

    vector<int> o(n);
    for(int i = 0; i < n; i++) o[i] = i;
    mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
    shuffle(o.begin(), o.end(), rng);
    for(int i = 0; i < n; i++) reduce_candidates(o[i]);
    for(int s = 0; s < n; s++) if(candidate[s]) bfs(s);

    return ans;
}

Compilation message (stderr)

keys.cpp: In function 'void bfs(int)':
keys.cpp:91:25: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   91 |     if(reachable.size() < P){
      |        ~~~~~~~~~~~~~~~~~^~~
keys.cpp:97:30: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   97 |     else if(reachable.size() == P){
      |             ~~~~~~~~~~~~~~~~~^~~~

• Subtask 1: 9 / 9
• Subtask 2: 11 / 11
• Subtask 3: 17 / 17
• Subtask 4: 0 / 30
• Subtask 5: 0 / 33