Submission #1227224

#	Time	Username	Problem	Language	Result	Execution time	Memory
1227224		emad234	Joker (BOI20_joker)	C++20	39 / 100	2095 ms	16064 KiB

Joker

#include <bits/stdc++.h>
#define ll long long
#define F first
#define S second
#define pii pair<int,int>
const ll mxN = 2e5 + 5,mod = 1e9 + 7;
using namespace std;
vector<vector<pii>>v;
int n;
int m,q;
bool ban[mxN],vis[mxN];
int color[mxN];
bool can;
void dfs(int u){
  vis[u] = 1;
  for(auto x : v[u]){
    if(ban[x.S]) continue;
    if(color[x.F] == -1) color[x.F] = !color[u];
    if(color[x.F] == color[u]) can = 1;
    if(!vis[x.F]){
      color[x.F] = !color[u];
      dfs(x.F);
    }
  }
}
bool solve(int l,int r){
  for(int i = 1;i <= n;i++){
    vis[i] = 0;
    color[i] = -1;
  }
  for(int i = 1;i <= m;i++){
    ban[i] = 0;
  }
  can = 0;
  for(int i = l;i <= r;i++) ban[i] = 1;
  for(int i = 1;i <= n;i++) if(!vis[i]) dfs(i);
  return can;
}
int ans[mxN];
signed main(){
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  cin >>n>>m>>q;
  v.resize(n + 4);
  for(int i = 1;i <= m;i++){
    int x,y;
    cin >>x>>y;
    v[x].push_back({y,i});
    v[y].push_back({x,i});
  }
  for(int i = 1; i <= min(m,1);i++){
    // cout<<i<<'\n';
    int l = i,r = m + 1;
    int md;
    while(l < r){
      md = (l + r) / 2;
      if(!solve(i,md)){
        ans[i] = md;
        r = md;
      }else l = md + 1;
    }
    ans[i] = l;
  }
  while(q--){
    int l,r;
    cin >>l>>r;
    // cout<<ans[l]<<' ';
    if(l <= 1) cout<<(r < ans[l] ? "YES\n" : "NO\n");
    else cout<<(solve(l,r) ? "YES\n" : "NO\n");
  }
}

• Subtask 1: 8 / 8
• Subtask 2: 25 / 25
• Subtask 3: 0 / 10
• Subtask 4: 0 / 22
• Subtask 5: 0 / 29
• Subtask 6: 6 / 6