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Submission #954441

# Submission time Handle Problem Language Result Execution time Memory
954441 2024-03-27T22:57:57 Z TAhmed33 Event Hopping (BOI22_events) C++
0 / 100
 1500 ms 6744 KB 
#include <bits/stdc++.h>
using namespace std;
const int MAXN = 1e5 + 25;
const int B = 18;
int dp[B][MAXN];
int n, q;
pair <int, int> a[MAXN];
int jump (int a, int b) {
	for (int i = B - 1; i >= 0; i--) {
		if (b & (1 << i)) {
			a = dp[i][a];
		}
	}
	return a;
}
int main () {
	ios::sync_with_stdio(0); cin.tie(0);
	cin >> n >> q;
	for (int i = 1; i <= n; i++) {
		cin >> a[i].first >> a[i].second;
	}
	for (int i = 1; i <= n; i++) {
		dp[0][i] = i;
		for (int j = 1; j <= n; j++) {
			if (a[j].second >= a[i].first && a[j].second <= a[i].second) {
				if (a[j].first < a[dp[0][i]].first) dp[0][i] = j;
			}
		}
	}
	for (int i = 1; i < B; i++) {
		for (int j = 1; j <= n; j++) {
			dp[i][j] = dp[i - 1][dp[i - 1][j]];
		}
	}
	while (q--) {
		int x, y; cin >> x >> y;
		if (x == y) {
			cout << "0\n";
			continue;
		}
		int ans = 0;
		if (a[y].first <= a[x].second) {
			ans = -1;
		} else {
			for (int i = B - 1; i >= 0; i--) {
				auto g = dp[i][y];
				if (!g) continue;
				if (a[g].first > a[x].second) {
					ans ^= 1 << i;
					y = g;
				}
			}
		}
		y = jump(y, ans + 1);
		if (a[x].second <= a[y].second && a[x].second >= a[y].first) {
			cout << ans + 2 << '\n';
		} else {
			cout << "impossible\n";
		}
	}
}

Subtask #1
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 6744 KB Output is correct
2 Execution timed out 1587 ms 2652 KB Time limit exceeded
3 Halted 0 ms 0 KB -

Subtask #2
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 6492 KB Output is correct
2 Correct 1 ms 6492 KB Output is correct
3 Incorrect 5 ms 6492 KB Output isn't correct
4 Halted 0 ms 0 KB -

Subtask #3
0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 6492 KB Output is correct
2 Correct 1 ms 6492 KB Output is correct
3 Incorrect 5 ms 6492 KB Output isn't correct
4 Halted 0 ms 0 KB -

Subtask #4
0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 6492 KB Output is correct
2 Correct 1 ms 6492 KB Output is correct
3 Incorrect 5 ms 6492 KB Output isn't correct
4 Halted 0 ms 0 KB -

Subtask #5
0 / 20.0

# Verdict Execution time Memory Grader output
1 Execution timed out 1554 ms 2652 KB Time limit exceeded
2 Halted 0 ms 0 KB -

Subtask #6
0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 6744 KB Output is correct
2 Execution timed out 1587 ms 2652 KB Time limit exceeded
3 Halted 0 ms 0 KB -