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Submission #603164

# Submission time Handle Problem Language Result Execution time Memory
603164 2022-07-23T16:21:03 Z MohamedAhmed04 Event Hopping (BOI22_events) C++14
40 / 100
 1500 ms 11016 KB 
#include <bits/stdc++.h>

using namespace std ;

const int inf = 1e9 ;
const int MAX = 2e5 + 10 ;

int L[MAX] , R[MAX] ;
int n , q ;

void compress()
{
	vector<int>v ;
	for(int i = 1 ; i <= n ; ++i)
		v.push_back(L[i]) , v.push_back(R[i]) ;
	sort(v.begin() , v.end()) ;
	v.erase(unique(v.begin() , v.end()) , v.end()) ;
	for(int i = 1 ; i <= n ; ++i)
	{
		L[i] = lower_bound(v.begin() , v.end() , L[i]) - v.begin() ;
		R[i] = lower_bound(v.begin() , v.end() , R[i]) - v.begin() ;
		L[i]++ , R[i]++ ;
	}
}

int dp[MAX] , ans[MAX] ;

vector< array<int , 3> >v ;

vector< pair<int , int> >queries[MAX] ;

bool cmp(array<int , 3>&a , array<int , 3>&b)
{
	if(a[1] != b[1])
		return (a[1] < b[1]) ;
	else
		return (a[0] < b[0]) ;
}

void solve(int st)
{
	if(!queries[st].size())
		return ;
	for(int i = 1 ; i <= n ; ++i)
		dp[i] = inf ;
	dp[st] = 0 ;
	stack<int>s ;
	s.push(st) ;
	for(auto &a : v)
	{
		int l = a[0] , r = a[1] , idx = a[2] ;
		if(idx == st || R[s.top()] > r)
			continue ;
		int last = -1 ;
		while(s.size() && R[s.top()] >= l)
		{
			last = s.top() ;
			s.pop() ;
		}
		if(last == -1)
			continue ;
		s.push(last) , s.push(idx) ;
		dp[idx] = dp[last] + 1 ;
	}
	for(auto &p : queries[st])
		ans[p.second] = dp[p.first] ;
}

int main()
{
	ios_base::sync_with_stdio(0) ;
	cin.tie(0) ;
	cin>>n>>q ;
	for(int i = 1 ; i <= n ; ++i)
		cin>>L[i]>>R[i] ;
	for(int i = 1 ; i <= q ; ++i)
	{
		int x , y ;
		cin>>x>>y ;
		queries[x].emplace_back(y , i) ;
	}
	compress() ;
	for(int i = 1 ; i <= n ; ++i)
		v.push_back({L[i] , R[i] , i}) ;
	sort(v.begin() , v.end() , cmp) ;
	for(int i = 1 ; i <= n ; ++i)
		solve(i) ;
	for(int i = 1 ; i <= q ; ++i)
	{
		if(ans[i] != inf)
			cout<<ans[i]<<"\n" ;
		else
			cout<<"impossible\n" ;
	}
	return 0 ;
}

Subtask #1
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 4948 KB Output is correct
2 Correct 94 ms 10628 KB Output is correct
3 Correct 686 ms 11016 KB Output is correct
4 Execution timed out 1581 ms 10788 KB Time limit exceeded
5 Halted 0 ms 0 KB -

Subtask #2
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 4948 KB Output is correct
2 Correct 3 ms 4924 KB Output is correct
3 Correct 3 ms 5076 KB Output is correct
4 Correct 4 ms 5076 KB Output is correct
5 Correct 4 ms 5080 KB Output is correct
6 Correct 4 ms 5076 KB Output is correct
7 Correct 4 ms 5076 KB Output is correct
8 Correct 4 ms 5076 KB Output is correct
9 Correct 3 ms 5076 KB Output is correct

Subtask #3
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 4948 KB Output is correct
2 Correct 3 ms 4924 KB Output is correct
3 Correct 3 ms 5076 KB Output is correct
4 Correct 4 ms 5076 KB Output is correct
5 Correct 4 ms 5080 KB Output is correct
6 Correct 4 ms 5076 KB Output is correct
7 Correct 4 ms 5076 KB Output is correct
8 Correct 4 ms 5076 KB Output is correct
9 Correct 3 ms 5076 KB Output is correct
10 Correct 3 ms 4948 KB Output is correct
11 Correct 3 ms 4948 KB Output is correct
12 Correct 3 ms 5076 KB Output is correct
13 Correct 3 ms 5076 KB Output is correct
14 Correct 3 ms 5076 KB Output is correct
15 Correct 4 ms 5076 KB Output is correct
16 Correct 4 ms 5076 KB Output is correct
17 Correct 4 ms 5076 KB Output is correct
18 Correct 3 ms 5076 KB Output is correct
19 Correct 51 ms 7128 KB Output is correct
20 Correct 49 ms 7192 KB Output is correct
21 Correct 197 ms 7836 KB Output is correct
22 Correct 201 ms 7884 KB Output is correct
23 Correct 244 ms 8736 KB Output is correct
24 Correct 177 ms 8652 KB Output is correct
25 Correct 53 ms 7944 KB Output is correct

Subtask #4
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 4948 KB Output is correct
2 Correct 3 ms 4924 KB Output is correct
3 Correct 3 ms 5076 KB Output is correct
4 Correct 4 ms 5076 KB Output is correct
5 Correct 4 ms 5080 KB Output is correct
6 Correct 4 ms 5076 KB Output is correct
7 Correct 4 ms 5076 KB Output is correct
8 Correct 4 ms 5076 KB Output is correct
9 Correct 3 ms 5076 KB Output is correct
10 Correct 3 ms 4948 KB Output is correct
11 Correct 3 ms 5028 KB Output is correct
12 Correct 4 ms 5076 KB Output is correct
13 Correct 3 ms 5012 KB Output is correct
14 Correct 4 ms 5076 KB Output is correct
15 Correct 4 ms 5076 KB Output is correct
16 Correct 4 ms 5044 KB Output is correct
17 Correct 4 ms 5076 KB Output is correct
18 Correct 3 ms 5076 KB Output is correct
19 Correct 83 ms 8888 KB Output is correct
20 Correct 146 ms 8812 KB Output is correct
21 Correct 155 ms 8928 KB Output is correct
22 Correct 115 ms 8908 KB Output is correct
23 Correct 144 ms 10672 KB Output is correct
24 Correct 97 ms 10796 KB Output is correct
25 Correct 31 ms 10152 KB Output is correct

Subtask #5
0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 93 ms 10676 KB Output is correct
2 Correct 659 ms 10932 KB Output is correct
3 Execution timed out 1581 ms 10828 KB Time limit exceeded
4 Halted 0 ms 0 KB -

Subtask #6
0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 4948 KB Output is correct
2 Correct 94 ms 10628 KB Output is correct
3 Correct 686 ms 11016 KB Output is correct
4 Execution timed out 1581 ms 10788 KB Time limit exceeded
5 Halted 0 ms 0 KB -