Submission #679548

#	Time	Username	Problem	Language	Result	Execution time	Memory
679548		penguin133	Event Hopping (BOI22_events)	C++17	10 / 100	1586 ms	136840 KiB

events

#include <bits/stdc++.h>
using namespace std;

#define int long long
#define pi pair<int, int>
#define pii pair<int, pi>
#define fi first
#define se second
#ifdef _WIN32
#define getchar_unlocked _getchar_nolock
#endif

vector<int> lmao[100005];
int S[100005], E[100005], dist[100005];
int n, q;

void solve(){
	cin >> n >> q;
	for(int i=1;i<=n;i++)cin >> S[i] >> E[i];
	set <pi> st;
	for(int i=1;i<=n;i++)st.insert({E[i], i});
	for(int i=1;i<=n;i++){
		set<pi> :: iterator it = st.lower_bound({S[i], 0});
		while(it != st.end()){
			pi tmp = *it;
			if(tmp.fi > E[i])break;
			lmao[tmp.se].push_back(i);
			it++;
		}
	}
	
	while(q--){
		int x, y; cin >> x >> y;
		queue<int>qu;
		for(int i=1;i<=n;i++)dist[i] = 1e9;
		dist[x] = 0;
		qu.push(x);
		while(!qu.empty()){
			int a = qu.front(); qu.pop();
			for(auto i : lmao[a]){
				if(dist[i] > dist[a] + 1)dist[i] = dist[a] + 1, qu.push(i);
			}
		}
		if(dist[y] != 1e9)cout << dist[y] << '\n';
		else cout << "impossible\n";
	}
}

main(){
	ios::sync_with_stdio(0);cin.tie(0);
	int tc = 1;
	//cin >> tc;
	for(int tc1=1;tc1<=tc;tc1++){
		// cout << "Case #" << tc1 << ": ";
		solve();
	}
}

Compilation message (stderr)

events.cpp:49:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   49 | main(){
      | ^~~~

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