oj.uz

Submission #1098174

# Submission time Handle Problem Language Result Execution time Memory
1098174 2024-10-09T05:57:21 Z rifat414141 Event Hopping (BOI22_events) C++17
30 / 100
 105 ms 30792 KB 
#include <bits/stdc++.h>
#define int long long int
#define endl '\n'
using namespace std;
const int N = 1e5 + 10;
const int INF = 1e18;
const int LOGN = 20;
int arr[N];
// pair<int, int> segment_tree[4 * N];
int up[N][LOGN];
int par[N];
// void build(int id, int l, int r)
// {
//     if (l == r)
//     {
//         segment_tree[id] = {arr[l - 1], l - 1};
//         return;
//     }
//     int mid = (l + r) / 2;
//     build(2 * id, l, mid);
//     build(2 * id + 1, mid + 1, r);
//     segment_tree[id] = min(segment_tree[2 * id], segment_tree[2 * id + 1]);
//     return;
// }
// pair<int, int> range(int id, int l, int r, int L, int R)
// {
//     if (R < l || L > r)
//     {
//         return {INF, INF};
//     }
//     if (L <= l && r <= R)
//     {
//         return segment_tree[id];
//     }
//     int mid = (l + r) / 2;
//     pair<int, int> x = range(2 * id, l, mid, L, R);
//     pair<int, int> y = range(2 * id + 1, mid + 1, r, L, R);
//     return min(x, y);
// }
struct Seg
{
    int siz;
    vector<pair<int, int>> v;

    void init(int n)
    {
        siz = 1;
        while (siz < n)
            siz *= 2;
        v.assign(siz * 2, make_pair(INF, -1));
    }

    pair<int, int> merge(pair<int, int> x, pair<int, int> y)
    {
        pair<int, int> res;
        res.first = min(x.first, y.first);
        if (x.first == y.first)
            res.second = min(x.second, y.second);
        else if (res.first == x.first)
            res.second = x.second;
        else
            res.second = y.second;
        return res;
    }

    void set(int i, pair<int, int> p, int x, int lx, int rx)
    {
        if (rx - lx == 1)
        {
            v[x] = merge(p, v[x]);
            return;
        }
        int m = (lx + rx) / 2;
        if (i < m)
            set(i, p, 2 * x + 1, lx, m);
        else
            set(i, p, 2 * x + 2, m, rx);
        v[x] = merge(v[2 * x + 1], v[2 * x + 2]);
    }

    void set(int i, pair<int, int> p)
    {
        set(i, p, 0, 0, siz);
    }

    pair<int, int> range_mx(int l, int r, int x, int lx, int rx)
    {
        if (l >= rx || lx >= r)
            return make_pair(INF, -1);
        if (lx >= l && rx <= r)
            return v[x];
        int m = (lx + rx) / 2;
        return merge(range_mx(l, r, 2 * x + 1, lx, m), range_mx(l, r, 2 * x + 2, m, rx));
    }

    pair<int, int> range_mx(int l, int r)
    {
        return range_mx(l, r, 0, 0, siz);
    }
};
void solve()
{
    int n, q;
    cin >> n >> q;
    vector<pair<int, int>> v1;
    vector<pair<int, pair<int, int>>> v2;
    for (int i = 0; i < n; ++i)
    {
        int l, r;
        cin >> l >> r;
        v1.push_back({l, r});
        v2.push_back({r, {l, i}});
    }
    int brr[n];
    sort(v2.begin(), v2.end());
    for (int i = 0; i < n; ++i)
    {
        arr[i] = v2[i].second.first;
        brr[v2[i].second.second] = i;
    }
    // build(1, 1, n);
    Seg st;
    st.init(n + 1);
    for (int i = n - 1; i >= 0; i--)
    {
        st.set(i, make_pair(v2[i].second.first, i));
    }

    for (int i = 0; i < n; ++i)
    {
        pair<int, pair<int, int>> p = {v2[i].second.first, {-1, -1}};
        int it = lower_bound(v2.begin(), v2.end(), p) - v2.begin();
        // cout << v2[i].first << ' ' << it << endl;
        if (it == i)
        {
            up[i][0] = par[i] = i;
        }
        else
        {
            // auto idx = range(1, 1, n, it + 1, i + 1);
            up[i][0] = par[i] = (st.range_mx(it, i)).second;
        }
    }
    for (int i = 1; i < LOGN; ++i)
    {
        for (int j = 0; j < n; ++j)
        {
            up[j][i] = up[up[j][i - 1]][i - 1];
        }
    }
    while (q--)
    {
        int s, e;
        cin >> s >> e;
        if (s == e)
        {
            cout << 0 << endl;
            continue;
        }
        s--, e--;
        s = brr[s], e = brr[e];
        int sl = v2[s].second.first, sr = v2[s].first;
        int el = v2[e].second.first, er = v2[e].first;
        if (s > e)
        {
            if (sl >= el && sr <= er)
            {
                cout << 1 << endl;
                continue;
            }
            else
            {
                cout << "impossible" << endl;
                continue;
            }
        }
        int curr = e;
        int ans = 0;
        for (int i = LOGN - 1; i >= 0; --i)
        {
            if (v2[up[curr][i]].first > sr)
            {
                ans += (1 << i);
                curr = up[curr][i];
            }
        }
        if (v2[up[curr][0]].first > sr)
        {
            ans++;
            curr = up[curr][0];
        }
        ans++;
        curr = up[curr][0];
        if (v2[curr].first > sr)
        {
            cout << "impossible" << endl;
            continue;
        }
        else
        {
            cout << ans << endl;
        }
    }
}

int32_t main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);
    // freopen("prime_subtractorization_input.txt", "r", stdin);
    // freopen("out.txt", "w", stdout);
    int t = 1;
    // cin >> t;
    for (int tt = 1; tt <= t; ++tt)
    {
        // cout << "Case #" << tt << ": ";
        solve();
    }

    return 0;
}

Subtask #1
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 468 KB Output is correct
2 Correct 79 ms 30272 KB Output is correct
3 Correct 84 ms 30276 KB Output is correct
4 Correct 89 ms 30148 KB Output is correct
5 Correct 85 ms 30216 KB Output is correct
6 Correct 82 ms 30272 KB Output is correct
7 Correct 76 ms 30280 KB Output is correct
8 Correct 73 ms 30792 KB Output is correct
9 Correct 70 ms 30572 KB Output is correct
10 Correct 101 ms 30576 KB Output is correct
11 Correct 86 ms 30708 KB Output is correct
12 Correct 65 ms 30024 KB Output is correct

Subtask #2
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 344 KB Output is correct
2 Correct 0 ms 464 KB Output is correct
3 Correct 1 ms 604 KB Output is correct
4 Correct 1 ms 752 KB Output is correct
5 Correct 1 ms 604 KB Output is correct
6 Incorrect 1 ms 604 KB Output isn't correct
7 Halted 0 ms 0 KB -

Subtask #3
0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 344 KB Output is correct
2 Correct 0 ms 464 KB Output is correct
3 Correct 1 ms 604 KB Output is correct
4 Correct 1 ms 752 KB Output is correct
5 Correct 1 ms 604 KB Output is correct
6 Incorrect 1 ms 604 KB Output isn't correct
7 Halted 0 ms 0 KB -

Subtask #4
0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 344 KB Output is correct
2 Correct 0 ms 464 KB Output is correct
3 Correct 1 ms 604 KB Output is correct
4 Correct 1 ms 752 KB Output is correct
5 Correct 1 ms 604 KB Output is correct
6 Incorrect 1 ms 604 KB Output isn't correct
7 Halted 0 ms 0 KB -

Subtask #5
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 83 ms 30276 KB Output is correct
2 Correct 81 ms 30276 KB Output is correct
3 Correct 94 ms 30388 KB Output is correct
4 Correct 73 ms 30788 KB Output is correct
5 Correct 87 ms 30436 KB Output is correct
6 Correct 94 ms 30308 KB Output is correct
7 Correct 105 ms 30276 KB Output is correct
8 Correct 92 ms 30540 KB Output is correct
9 Correct 52 ms 28484 KB Output is correct
10 Correct 78 ms 29968 KB Output is correct
11 Correct 73 ms 29748 KB Output is correct
12 Correct 76 ms 30016 KB Output is correct

Subtask #6
0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 468 KB Output is correct
2 Correct 79 ms 30272 KB Output is correct
3 Correct 84 ms 30276 KB Output is correct
4 Correct 89 ms 30148 KB Output is correct
5 Correct 85 ms 30216 KB Output is correct
6 Correct 82 ms 30272 KB Output is correct
7 Correct 76 ms 30280 KB Output is correct
8 Correct 73 ms 30792 KB Output is correct
9 Correct 70 ms 30572 KB Output is correct
10 Correct 101 ms 30576 KB Output is correct
11 Correct 86 ms 30708 KB Output is correct
12 Correct 65 ms 30024 KB Output is correct
13 Correct 1 ms 344 KB Output is correct
14 Correct 0 ms 464 KB Output is correct
15 Correct 1 ms 604 KB Output is correct
16 Correct 1 ms 752 KB Output is correct
17 Correct 1 ms 604 KB Output is correct
18 Incorrect 1 ms 604 KB Output isn't correct
19 Halted 0 ms 0 KB -