oj.uz

Submission #868538

# Submission time Handle Problem Language Result Execution time Memory
868538 2023-10-31T17:33:43 Z Dec0Dedd Event Hopping (BOI22_events) C++14
30 / 100
 93 ms 33992 KB 
#include <bits/stdc++.h>

using namespace std;

typedef pair<int, int> pii;

const int N = 1e5+10;
const int K = 20;
const int INF = 1e6+10;

int up[K][N], d[K][N], s[N], lf[N], e[N], mx[N], idx[N], n, q;
vector<pii> v;
vector<int> add[N], rm[N];

bool cmp(pii a, pii b) {
    if (a.first == b.first) return s[a.second] < s[b.second];
    else return a.first < b.first;
}

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

    cin>>n>>q;
    for (int i=0; i<n; ++i) {
        cin>>s[i]>>e[i];
        v.push_back({e[i], i});
    } sort(v.begin(), v.end(), cmp);

    for (int i=0; i<n; ++i) {
        int j=lower_bound(v.begin(), v.end(), make_pair(s[v[i].second], -1))-v.begin();
        lf[i]=j;
        add[lf[i]].push_back(v[i].second);
        rm[i+1].push_back(v[i].second);
    }

    for (int i=0; i<n; ++i) idx[v[i].second]=i;

    multiset<pii> ms;
    for (int i=0; i<n; ++i) {
        for (auto u : add[i]) ms.insert({e[u], idx[u]});
        for (auto u : rm[i]) ms.erase(ms.find({e[u], idx[u]}));
        mx[i]=ms.rbegin()->second;
    }

    for (int i=n-1; i>=0; --i) {
        up[0][i]=mx[i], d[0][i]=(mx[i] != i);
        for (int j=1; j<K; ++j) {
            up[j][i]=up[j-1][up[j-1][i]];
            d[j][i]=d[j-1][i]+d[j-1][up[j-1][i]];
        }
    }

    /*
    cout<<"v: ";
    for (int i=0; i<n; ++i) cout<<v[i].first<<" ";
    cout<<"\n";

    cout<<"idx: ";
    for (int i=0; i<n; ++i) cout<<idx[i]<<" ";
    cout<<"\n";

    cout<<"mx: ";
    for (int i=0; i<n; ++i) cout<<mx[i]<<" ";
    cout<<"\n";
    */

    while (q--) {
        int l, r; cin>>l>>r; --l, --r;
        l=idx[l], r=idx[r];

        //cout<<"QUE "<<l<<", "<<r<<"\n";

        if (l == r) {
            cout<<0<<"\n";
            continue;
        }

        if (v[r].first < v[l].first) {
            cout<<"impossible\n";
            continue;
        }

        int ans=0;
        for (int j=K-1; j>=0; --j) {
            //cout<<"HERE "<<up[j][l]<<"\n";
            if (up[j][l] <= r) ans+=d[j][l], l=up[j][l];
        }

        if (l == r) ans+=0;
        else {
            if (s[v[r].second] <= e[v[l].second] && e[v[l].second] <= e[v[r].second]) ++ans, l=r;
            else {
                cout<<"impossible\n";
                continue;
            }
        }

        assert(l == r);
        cout<<ans<<"\n";
    }
}

Subtask #1
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 21140 KB Output is correct
2 Correct 72 ms 30240 KB Output is correct
3 Correct 75 ms 33480 KB Output is correct
4 Correct 80 ms 33488 KB Output is correct
5 Correct 79 ms 33504 KB Output is correct
6 Correct 71 ms 33428 KB Output is correct
7 Correct 81 ms 33540 KB Output is correct
8 Correct 67 ms 33992 KB Output is correct
9 Correct 67 ms 33760 KB Output is correct
10 Correct 88 ms 33660 KB Output is correct
11 Correct 77 ms 33740 KB Output is correct
12 Correct 61 ms 31436 KB Output is correct

Subtask #2
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 21336 KB Output is correct
2 Correct 3 ms 21084 KB Output is correct
3 Correct 3 ms 21260 KB Output is correct
4 Correct 3 ms 21144 KB Output is correct
5 Incorrect 3 ms 21084 KB Output isn't correct
6 Halted 0 ms 0 KB -

Subtask #3
0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 21336 KB Output is correct
2 Correct 3 ms 21084 KB Output is correct
3 Correct 3 ms 21260 KB Output is correct
4 Correct 3 ms 21144 KB Output is correct
5 Incorrect 3 ms 21084 KB Output isn't correct
6 Halted 0 ms 0 KB -

Subtask #4
0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 21336 KB Output is correct
2 Correct 3 ms 21084 KB Output is correct
3 Correct 3 ms 21260 KB Output is correct
4 Correct 3 ms 21144 KB Output is correct
5 Incorrect 3 ms 21084 KB Output isn't correct
6 Halted 0 ms 0 KB -

Subtask #5
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 73 ms 30316 KB Output is correct
2 Correct 73 ms 33288 KB Output is correct
3 Correct 83 ms 33448 KB Output is correct
4 Correct 68 ms 33944 KB Output is correct
5 Correct 78 ms 33740 KB Output is correct
6 Correct 79 ms 33484 KB Output is correct
7 Correct 93 ms 33420 KB Output is correct
8 Correct 79 ms 32208 KB Output is correct
9 Correct 57 ms 33488 KB Output is correct
10 Correct 73 ms 33212 KB Output is correct
11 Correct 93 ms 33556 KB Output is correct
12 Correct 72 ms 33232 KB Output is correct

Subtask #6
0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 21140 KB Output is correct
2 Correct 72 ms 30240 KB Output is correct
3 Correct 75 ms 33480 KB Output is correct
4 Correct 80 ms 33488 KB Output is correct
5 Correct 79 ms 33504 KB Output is correct
6 Correct 71 ms 33428 KB Output is correct
7 Correct 81 ms 33540 KB Output is correct
8 Correct 67 ms 33992 KB Output is correct
9 Correct 67 ms 33760 KB Output is correct
10 Correct 88 ms 33660 KB Output is correct
11 Correct 77 ms 33740 KB Output is correct
12 Correct 61 ms 31436 KB Output is correct
13 Correct 3 ms 21336 KB Output is correct
14 Correct 3 ms 21084 KB Output is correct
15 Correct 3 ms 21260 KB Output is correct
16 Correct 3 ms 21144 KB Output is correct
17 Incorrect 3 ms 21084 KB Output isn't correct
18 Halted 0 ms 0 KB -