Submission #593954

#	Time	Username	Problem	Language	Result	Execution time	Memory
593954		CaroLinda	Event Hopping (BOI22_events)	C++14	0 / 100	1581 ms	4180 KiB

events

#include <bits/stdc++.h>

//bad complexity to test idea

#define ll long long

const int MAXN = 1010;

using namespace std;

int N, Q;
int S[MAXN], E[MAXN];
int nxt[MAXN];
int mat[MAXN][MAXN];

void findNxtArray(){
	for(int i = 1; i <= N; i++){
		nxt[i] = -1;
		mat[i][i] = 1;

		for(int j = 1; j <= N; j++){
			if(j == i) 
				continue;
			if(!(E[j] >= S[i] && E[j] <= E[i]))
				continue;

			mat[i][j] = 1;

			if(nxt[i] == -1 || S[nxt[i]] > S[j])
				nxt[i] = j;
		}
	}
}

int main(){
	ios_base::sync_with_stdio(false);
	cin.tie(0);

	cin >> N >> Q;
	for(int i = 1; i <= N; i++)
		cin >> S[i] >> E[i];

	findNxtArray();

	for(int i = 1, a, b; i <= Q; i++){
		cin >> a >> b;

		int ans = 0;

		while(!mat[b][a] && nxt[b] != -1){
			b = nxt[b];
			ans++;
		}

		ans += (a != b);

		if(nxt[b] == -1 || !mat[b][a]){
			cout << "impossible\n";
		}
		else cout << ans << "\n";
	}
}

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