Submission #646022

#	Time	Username	Problem	Language	Result	Execution time	Memory
646022		GaLz	Event Hopping (BOI22_events)	C++14	10 / 100	1582 ms	130732 KiB

events

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<ll, ll> pll;
typedef pair<int, int> pii;
typedef vector<int> vi;
typedef vector<ll> vll;
const ll mod=1e9+7;
const ll maxn=1e5+5;
const int INF=1e8;
#define ok ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
#define fi first
#define se second
#define pb push_back
#define ub upper_bound
#define lb lower_bound
#define endl '\n'
vi adj[maxn];
int n, q, dis[5001][5001], u, v;
pii arr[maxn];
int main() {
    ok
    cin >> n >> q;
    for(int i=1; i<=n; i++) cin >> arr[i].fi >> arr[i].se;
    if(n<=5000) {
        for(int i=1; i<=n; i++) {
            for(int j=1; j<=n; j++) {
                if(i==j) continue;
                if(arr[i].se>=arr[j].fi && arr[i].se<=arr[j].se) adj[i].pb(j);
            }
        }
        memset(dis, -1, sizeof dis);
        for(int i=1; i<=n; i++) {
            dis[i][i]=0;
            queue<int> qu;
            qu.push(i);
            while(!qu.empty()) {
                int fr=qu.front(); qu.pop();
                for(auto it : adj[fr]) {
                    if(dis[i][it]==-1) {
                        dis[i][it]=dis[i][fr]+1;
                        qu.push(it);
                    }
                }
            }
        }
        while(q--) {
            cin >> u >> v;
            if(dis[u][v]==-1) cout << "impossible";
            else cout << dis[u][v];
            cout << endl;
        }
    }
}

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