oj.uz

Submission #580223

# Submission time Handle Problem Language Result Execution time Memory
580223 2022-06-20T18:24:53 Z penguinhacker Event Hopping (BOI22_events) C++17
10 / 100
 111 ms 14672 KB 
#include <bits/stdc++.h>
using namespace std;

#define ll long long
#define ar array

const int mxN=1e5;
int n, q, ls[2*mxN], rs[2*mxN], ans[mxN];
ar<int, 2> segs[mxN];
vector<int> d;
vector<ar<int, 3>> qry[2*mxN];

struct ft {
	int ft[2*mxN+1];
	void upd(int i, int x) {
		for (++i; i<=2*n; i+=i&-i)
			ft[i]+=x;
	}
	int qry(int i) {
		int r=0;
		for (++i; i; i-=i&-i)
			r+=ft[i];
		return r;
	}
} bad, distinct;

int main() {
	ios::sync_with_stdio(0);
	cin.tie(0);
	cin >> n >> q;
	for (int i=0; i<n; ++i) {
		cin >> segs[i][0] >> segs[i][1];
		d.push_back(segs[i][0]);
		d.push_back(segs[i][1]);
	}
	sort(d.begin(), d.end());
	d.resize(unique(d.begin(), d.end())-d.begin());
	memset(ls, -1, sizeof(ls));
	for (int i=0; i<n; ++i) {
		segs[i][0]=lower_bound(d.begin(), d.end(), segs[i][0])-d.begin();
		segs[i][1]=lower_bound(d.begin(), d.end(), segs[i][1])-d.begin();
		//cout << "seg  " <<  segs[i][0] << " " << segs[i][1] << endl;
		if (ls[segs[i][1]]==-1||segs[i][0]<ls[segs[i][1]])
			ls[segs[i][1]]=segs[i][0];
	}
	for (int i=0; i<q; ++i) {
		int a, b;
		cin >> a >> b, --a, --b;
		ans[i]=-1;
		if (segs[a][1]<segs[b][1])
			qry[segs[b][1]].push_back({segs[a][1], segs[b][0], i});
		if (segs[a][1]==segs[b][1])
			ans[i]=a!=b;
	}
	iota(rs, rs+d.size(), 0);
	vector<int> ends, bads, end_val;
	for (int i=0; i<d.size(); ++i) {
		distinct.upd(i, 1);
		if (ls[i]!=-1) {
			int last;
			while(ends.size()&&ends.back()>=ls[i]) {
				distinct.upd(ends.back(), -1);
				ends.pop_back();
				last=end_val.back();
				end_val.pop_back();
			}
			if ((ends.empty()&&ls[i])||ends.size()&&ends.back()<ls[i]-1) {
				ends.push_back(ls[i]-1);
				distinct.upd(ls[i]-1, 1);
				end_val.push_back(last);
			}
			while(bads.size()&&ls[i]<=bads.back()) {
				bad.upd(bads.back(), -1);
				bads.pop_back();
			}
		}
		/*cout << i << ": ";
		for (int j : end_val)
			cout << j << " ";
		cout << endl;*/
		for (auto [s, bound, ind] : qry[i]) {
			if (bad.qry(i-1)-bad.qry(s-1))
				continue;
			assert(ls[i]<i);
			int cur=distinct.qry(i-1)-distinct.qry(s-1);
			int pos=cur?end_val.back():s;
			//cout << cur << " " << pos << " " << end_val.back() << endl;
			ans[ind]=cur+1+(pos<bound);
		}
		bad.upd(i, 1);
		ends.push_back(i);
		end_val.push_back(i);
		bads.push_back(i);
	}
	for (int i=0; i<q; ++i) {
		if (ans[i]==-1)
			cout << "impossible\n";
		else
			cout << ans[i] << "\n";
	}
	return 0;
}

Compilation message

events.cpp: In function 'int main()':
events.cpp:57:17: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   57 |  for (int i=0; i<d.size(); ++i) {
      |                ~^~~~~~~~~
events.cpp:67:42: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
   67 |    if ((ends.empty()&&ls[i])||ends.size()&&ends.back()<ls[i]-1) {
      |                               ~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~

Subtask #1
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 5716 KB Output is correct
2 Correct 95 ms 11972 KB Output is correct
3 Correct 95 ms 12492 KB Output is correct
4 Correct 100 ms 12340 KB Output is correct
5 Correct 98 ms 12612 KB Output is correct
6 Correct 98 ms 12692 KB Output is correct
7 Correct 104 ms 12684 KB Output is correct
8 Correct 94 ms 14664 KB Output is correct
9 Correct 89 ms 14652 KB Output is correct
10 Correct 102 ms 12356 KB Output is correct
11 Correct 103 ms 12360 KB Output is correct
12 Correct 55 ms 12204 KB Output is correct

Subtask #2
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 5716 KB Output is correct
2 Correct 3 ms 5716 KB Output is correct
3 Correct 4 ms 5844 KB Output is correct
4 Correct 4 ms 5844 KB Output is correct
5 Correct 4 ms 5844 KB Output is correct
6 Incorrect 4 ms 5844 KB Output isn't correct
7 Halted 0 ms 0 KB -

Subtask #3
0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 5716 KB Output is correct
2 Correct 3 ms 5716 KB Output is correct
3 Correct 4 ms 5844 KB Output is correct
4 Correct 4 ms 5844 KB Output is correct
5 Correct 4 ms 5844 KB Output is correct
6 Incorrect 4 ms 5844 KB Output isn't correct
7 Halted 0 ms 0 KB -

Subtask #4
0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 5716 KB Output is correct
2 Correct 3 ms 5716 KB Output is correct
3 Correct 4 ms 5844 KB Output is correct
4 Correct 4 ms 5844 KB Output is correct
5 Correct 4 ms 5844 KB Output is correct
6 Incorrect 4 ms 5844 KB Output isn't correct
7 Halted 0 ms 0 KB -

Subtask #5
0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 98 ms 11976 KB Output is correct
2 Correct 94 ms 12416 KB Output is correct
3 Correct 97 ms 12396 KB Output is correct
4 Correct 91 ms 14672 KB Output is correct
5 Correct 94 ms 12380 KB Output is correct
6 Incorrect 111 ms 13272 KB Output isn't correct
7 Halted 0 ms 0 KB -

Subtask #6
0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 5716 KB Output is correct
2 Correct 95 ms 11972 KB Output is correct
3 Correct 95 ms 12492 KB Output is correct
4 Correct 100 ms 12340 KB Output is correct
5 Correct 98 ms 12612 KB Output is correct
6 Correct 98 ms 12692 KB Output is correct
7 Correct 104 ms 12684 KB Output is correct
8 Correct 94 ms 14664 KB Output is correct
9 Correct 89 ms 14652 KB Output is correct
10 Correct 102 ms 12356 KB Output is correct
11 Correct 103 ms 12360 KB Output is correct
12 Correct 55 ms 12204 KB Output is correct
13 Correct 3 ms 5716 KB Output is correct
14 Correct 3 ms 5716 KB Output is correct
15 Correct 4 ms 5844 KB Output is correct
16 Correct 4 ms 5844 KB Output is correct
17 Correct 4 ms 5844 KB Output is correct
18 Incorrect 4 ms 5844 KB Output isn't correct
19 Halted 0 ms 0 KB -