Submission #1295288

#	Time	Username	Problem	Language	Result	Execution time	Memory
1295288		hihihihaw	Event Hopping (BOI22_events)	C++20	0 / 100	1596 ms	7316 KiB

events

#pragma GCC optimize("O3,unroll-loops")    
#include <bits/stdc++.h>
using namespace std;
 
#define int long long
#define ll long long
#define pb push_back
#define pii pair<int,int>
#define sz(v) (int)v.size()
#define fi first
#define se second
#define INF 1223372036854775807
#define INF2 122337203
#define MOD 998244353
#define cint(x) int x;cin>>x;
#define cinarr(a,n) int a[n];for (int i=0;i<n;i++) cin>>a[i];
#define coutarr(a) for (auto d:a)cout<<d<<" "; cout<<endl;
#define coutarrD(a) for (auto d:a) cout<<d.fi<<","<<d.se<<" "; cout<<endl;
#define BERKAY_TUP ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL)
#define endl '\n'
#define ld long double
#define mid (start+end)/2
#define vvi vector<vector<int>>
int t=1;
int interactive=0;
int usaco=0;
int testCase=0;

void solve(){
    int n,q;
    cin>>n>>q;
    vector<vector<int>> v;
    for (int i=0;i<n;i++){
        int x,y;
        cin>>x>>y;
        v.pb({y,x,i+1});
    }
    int z[n+1];
    sort(v.begin(),v.end());
    for (int i=0;i<n;i++){
        z[v[i][2]]=i+1;
    }
    int g[n+1];
    for (int i=0;i<n;i++){
        int mx=-1;
        int mxV=-2;
        for (int j=i+1;j<n;j++){
            if (v[i][0]<=v[j][0] && v[j][1]<=v[i][0]){
                mx=max(mx,v[j][0]);
                mxV=j;
            }
        }
        g[i+1]=mxV+1;
    }
    
    while (q--){
        int a,b;
        cin>>a>>b;
        a=z[a];
        b=z[b];
        int ans=0;
        while (23){
            if (a==b) break;
            if (v[a-1][0]<=v[b-1][0] && v[b-1][1]<=v[a-1][0]){
                ans++;
                cout<<ans<<endl;
                ans=-1;
                break;
            }
            else if (g[a]!=-1 && g[a]<=b){
                a=g[a];
                ans++;
            }
            else{
                if (v[a-1][0]<=v[b-1][0] && v[b-1][1]<=v[a-1][0]){
                    ans++;
                    cout<<ans<<endl;
                    ans=-1;
                    break;
                }
                else{
                    ans=-1;
                    cout<<"impossible"<<endl;
                    break;
                }
            }
        }
        if (ans!=-1) cout<<ans<<endl;
    }

    
   
}

 
 
 
 
 
 

 
int32_t main(){
    BERKAY_TUP;
    if (usaco){
        freopen("team.in", "r", stdin);
        freopen("team.out", "w", stdout);
    }
    if (!interactive){
    #ifdef Local
        freopen("in.txt", "r", stdin);
        freopen("out2.txt", "w", stdout);
        //freopen("wormsort.out", "w", stdout);
    #endif
    }
    if (t==1) solve();
    else{
        cin>>t;
        while (t--){testCase++;solve();}
    }
    
        
    return 0;
}

Compilation message (stderr)

events.cpp: In function 'int32_t main()':
events.cpp:106:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  106 |         freopen("team.in", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
events.cpp:107:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  107 |         freopen("team.out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 10
• Subtask 2: 0 / 10
• Subtask 3: 0 / 15
• Subtask 4: 0 / 15
• Subtask 5: 0 / 20
• Subtask 6: 0 / 30