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Submission #601031

# Submission time Handle Problem Language Result Execution time Memory
601031 2022-07-21T10:17:36 Z CSQ31 Event Hopping (BOI22_events) C++17
25 / 100
 1500 ms 4652 KB 
#include <bits/stdc++.h>
using namespace std;
#define all(a) a.begin(),a.end()
#define owo ios_base::sync_with_stdio(0);cin.tie(0);
const int MAXN = 1e5+1;
int s[MAXN],e[MAXN];
int main()
{
	owo
	int n,q;
	cin>>n>>q;
	vector<int>crd;
	for(int i=0;i<n;i++)cin>>s[i]>>e[i];
	for(int i=0;i<n;i++){
		crd.push_back(s[i]);
		crd.push_back(e[i]);
	}
	sort(all(crd));
	crd.resize(unique(all(crd)) - crd.begin());
	for(int i=0;i<n;i++){
		s[i] = lower_bound(all(crd),s[i]) - crd.begin()+1;
		e[i] = lower_bound(all(crd),e[i]) - crd.begin()+1;
	}
	int m = crd.size();
	vector<int>mn(m+1);
	for(int i=1;i<=m;i++)mn[i] = i;
	for(int i=0;i<n;i++){
		mn[e[i]] = min(mn[e[i]],s[i]);
		
	}
	//cout<<"range"<<'\n';
	//for(int i=0;i<n;i++)cout<<s[i]<<" "<<e[i]<<'\n';
	//for(int i=1;i<=m;i++)cout<<mn[i]<<" ";
	//cout<<'\n';
	
	//greedy backwards
	//forward fails because we are going to exact nodes
	while(q--){
		int l,r;
		cin>>l>>r;
		l--;
		r--;
		if(l==r){
			cout<<0<<'\n';
			continue;
		}
		if(e[l] > e[r]){
			cout<<"impossible"<<'\n';
			continue;
		}
		int cur = s[r];
		int last = e[r];
		int ans = 1;
		while(cur > e[l]){
			int best = cur;
			for(int i=cur;i<=last;i++)best = min(best,mn[i]);
			if(best == cur){
				ans = -1;
				break;
			}
			last = cur;
			cur = best;
			ans++;
		}
		if(ans==-1)cout<<"impossible"<<'\n';
		else cout<<ans<<'\n';
	}
	
	
}

Subtask #1
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Execution timed out 1558 ms 2904 KB Time limit exceeded
3 Halted 0 ms 0 KB -

Subtask #2
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 0 ms 212 KB Output is correct
3 Correct 1 ms 340 KB Output is correct
4 Correct 2 ms 348 KB Output is correct
5 Correct 1 ms 340 KB Output is correct
6 Correct 1 ms 448 KB Output is correct
7 Correct 2 ms 352 KB Output is correct
8 Correct 1 ms 340 KB Output is correct
9 Correct 1 ms 340 KB Output is correct

Subtask #3
0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 0 ms 212 KB Output is correct
3 Correct 1 ms 340 KB Output is correct
4 Correct 2 ms 348 KB Output is correct
5 Correct 1 ms 340 KB Output is correct
6 Correct 1 ms 448 KB Output is correct
7 Correct 2 ms 352 KB Output is correct
8 Correct 1 ms 340 KB Output is correct
9 Correct 1 ms 340 KB Output is correct
10 Correct 1 ms 212 KB Output is correct
11 Correct 1 ms 212 KB Output is correct
12 Correct 1 ms 348 KB Output is correct
13 Correct 1 ms 352 KB Output is correct
14 Correct 1 ms 340 KB Output is correct
15 Correct 1 ms 244 KB Output is correct
16 Correct 2 ms 340 KB Output is correct
17 Correct 1 ms 384 KB Output is correct
18 Correct 1 ms 340 KB Output is correct
19 Correct 1227 ms 1904 KB Output is correct
20 Execution timed out 1594 ms 1824 KB Time limit exceeded
21 Halted 0 ms 0 KB -

Subtask #4
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 0 ms 212 KB Output is correct
3 Correct 1 ms 340 KB Output is correct
4 Correct 2 ms 348 KB Output is correct
5 Correct 1 ms 340 KB Output is correct
6 Correct 1 ms 448 KB Output is correct
7 Correct 2 ms 352 KB Output is correct
8 Correct 1 ms 340 KB Output is correct
9 Correct 1 ms 340 KB Output is correct
10 Correct 0 ms 212 KB Output is correct
11 Correct 0 ms 212 KB Output is correct
12 Correct 1 ms 340 KB Output is correct
13 Correct 1 ms 352 KB Output is correct
14 Correct 1 ms 340 KB Output is correct
15 Correct 1 ms 340 KB Output is correct
16 Correct 1 ms 340 KB Output is correct
17 Correct 1 ms 352 KB Output is correct
18 Correct 1 ms 340 KB Output is correct
19 Correct 99 ms 2660 KB Output is correct
20 Correct 60 ms 3364 KB Output is correct
21 Correct 68 ms 3976 KB Output is correct
22 Correct 69 ms 4248 KB Output is correct
23 Correct 64 ms 4644 KB Output is correct
24 Correct 87 ms 4652 KB Output is correct
25 Correct 23 ms 3428 KB Output is correct

Subtask #5
0 / 20.0

# Verdict Execution time Memory Grader output
1 Execution timed out 1544 ms 2976 KB Time limit exceeded
2 Halted 0 ms 0 KB -

Subtask #6
0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Execution timed out 1558 ms 2904 KB Time limit exceeded
3 Halted 0 ms 0 KB -