제출 #896397

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
896397		karamkallasi	Event Hopping (BOI22_events)	C++14	10 / 100	1582 ms	307652 KiB

events

#include <bits/stdc++.h>
#define T ll tt ; cin>>tt ; while(tt--)
#define fast ios::sync_with_stdio(NULL); cin.tie(0); cout.tie(0);
#define endl '\n'
#define yes void (cout << "YES" << endl)
#define no void (cout << "NO" << endl)
#define pb push_back
#define F first
#define S second
#define ld long double
#define fixed(g) fixed<<setprecision(g)
#define ll long long
using namespace std;
const ll N = 2e6 + 9 ;
const ll oo = 1e18 + 7 ;
ll n , m , k , x , y , z , ind , ans , a[N] , b[N] , mn , sz[N] , dp[5009][5009];
bool vis[N] , ff , ok[N];
vector<ll>v[N];
void bfs(ll x){
    for(ll i=1 ; i<=n ; i++){
        vis[i] = 0 ;
        sz[i] = 0 ;
    }
    queue<ll> q ;
    q.push(x) ;
    while(!q.empty()){
       ll node = q.front() ;
       q.pop() ;
       vis[node] = 1 ;
       for(auto e : v[node]){
            if(vis[e])continue ;
            vis[e] = 1 ;
            sz[e] = sz[node] + 1 ;
            dp[x][e] = sz[e] ;
            q.push(e);
       }
    }
}
int main(){
fast
    cin >> n >> m ;
    for(ll i=1 ; i<=n ; i++){
        cin >> a[i] >> b[i] ;
    }
    for(ll i=1 ; i<=n ; i++){
        for(ll j=1 ; j<=n ; j++){
            if(i==j)continue ;
            dp[i][j] = -1 ;
            if(a[j]<=b[i] && b[i]<=b[j])
                v[i].pb(j);
        }
    }
    while(m--){
        cin >> x >> y ;
        if(x==y)cout<<0<<endl;
        else{
            if(ok[x]){
                if(dp[x][y]==-1)cout<<"impossible"<<endl;
                else cout<<dp[x][y]<<endl ;
                continue ;
            }
            ok[x] = 1 ;
            bfs(x) ;
            if(sz[y]==0)cout<<"impossible"<<endl ;
            else cout<<sz[y]<<endl ;
        }
    }
    return 0 ;
}

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