Submission #1358285

#TimeUsernameProblemLanguageResultExecution timeMemory
1358285JohanAlternating Heights (CCO22_day1problem1)C++20
0 / 25
1094 ms3480 KiB
#include <bits/stdc++.h>
using namespace std;
#define int long long
const int N = 2e5 + 5;
int a[N];
bool is_cycle = false;
vector < int > color, adj[N];
void dfs(int u){
  if(is_cycle)return;
  color[u] = 1;
  for(auto v : adj[u]){
    if(color[v] == -1)
      dfs(v);
    else if(color[v] == 1){
      is_cycle = true;
      return;
    }
  }
  color[u] = 2;
}
signed main(){
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  int n, k, q;
  cin >> n >> k >> q;
  for(int i = 1; i <= n; i++)
    cin >> a[i];
  while(q--){
    int l, r;
    cin >> l >> r;
    color.assign(k + 1, -1);
    for(int i = l; i < r; i++){
      if((i - l + 1) % 2 == 0){
        adj[a[i]].push_back(a[i + 1]);
      }
      else{
        adj[a[i + 1]].push_back(a[i]);
      }
    }
    is_cycle = false;
    dfs(1);
    for(int i = 1; i <= k; i++)
      adj[i].clear();
    cout << (is_cycle ? "NO" : "YES") << endl;
  }
}
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