Submission #678083

#	Time	Username	Problem	Language	Result	Execution time	Memory
678083		qwerasdfzxcl	Keys (IOI21_keys)	C++17	Compilation error	0 ms	0 KiB

keys

#include <bits/stdc++.h>
using namespace std;
const int n_max = 301000;
const int k_max = 301000;
 
vector<pair<int,int>> adj[n_max];
bool visited[n_max];
int original_key[n_max];
int has_key[k_max];
vector<int> blocked[k_max];
 
vector<int> P, INV;
 
void erase_all(vector<int> st1, vector<int> st2, vector<int> st3){
  for (auto &x:st1) visited[x] = false;
  for (auto &x:st2) has_key[x] = false;
  for (auto &x:st3) blocked[x].clear();
}
 
int n;
vector<int> ans;
 
int explore(int x, bool flag=0) {
  	int ox = x;
    for(int i=0; i<n; i++) {
        visited[i] = false;
        has_key[i] = false;
        blocked[i].clear();
    }
  
  vector<int> st1, st2, st3;
  
    visited[x] = true; st1.push_back(x);
    queue<int> q;
    q.push(x);
    int ans = 0;
    while(!q.empty()) {
        const int next = q.front();
        q.pop();
        ans++;
 
        int new_key = original_key[next];
        if(!has_key[new_key]) {
          	
            has_key[new_key] = true; st2.push_back(new_key);
            for(int i: blocked[new_key]) {
                if(!visited[i]) {
                    visited[i] = true; st1.push_back(i);
                  	if (INV[i] < INV[ox]){
                      erase_all(st1, st2, st3);
                      return -1;
                    }
                    q.push(i);
                }
            }
        }
        for(pair<int,int> p: adj[next]) {
            if(has_key[p.first]) { // i have the key
                if(!visited[p.second]) { // put in the queue
                    visited[p.second] = true; st1.push_back(p.second);
                  	if (INV[p.second] < INV[ox]){
                      erase_all(st1, st2, st3);
                      return -1;
                    } 
                    q.push(p.second);
                }
            } else { // it may be unblocked later
                //assert(p.first < k_max);
                blocked[p.first].push_back(p.second); st3.push_back(p.first);
            }
        }
    }
  	if (flag) for (auto &x:st1) ans[x] = 1;
  	erase_all(st1, st2, st3);
    return ans;
}
 
vector<int> find_reachable(vector<int> r, vector<int> u, vector<int> v, vector<int> c) {
    int m = c.size();
    n = r.size();
    for(int i=0; i<n; i++) {
        original_key[i] = r[i];
    }
    for(int i=0; i<m; i++) {
        adj[u[i]].emplace_back(c[i], v[i]);
        adj[v[i]].emplace_back(c[i], u[i]);
    }
  	
  	for (int i=0;i<n;i++) P.push_back(i);
  	mt19937 rng(694201557);
  	shuffle(P.begin(), P.end(), rng);
  	INV.resize(n);
  	for (int i=0;i<n;i++) INV[P[i]] = i;
  
    int a[n];
    int s = n+1;
  	vector<int> candidate;
  
    for(int i=0; i<n; i++) {
      	int v = P[i];
        a[v] = explore(v);
      	if (a[v]!=-1){
          if (s > a[v]){
            candidate.clear();
            s = a[v];
            candidate.push_back(v);
          }
          else if (s==a[v]){
            candidate.push_back(v);
          }
        }
    }
    
  	ans.resize(n);
  	for (auto &x:candidate) explore(x, 1);
 
    return ans;
}

Compilation message (stderr)

keys.cpp: In function 'int explore(int, bool)':
keys.cpp:73:35: error: invalid types 'int[int]' for array subscript
   73 |    if (flag) for (auto &x:st1) ans[x] = 1;
      |                                   ^