oj.uz

Submission #1098221

# Submission time Handle Problem Language Result Execution time Memory
1098221 2024-10-09T06:34:28 Z rifat414141 Event Hopping (BOI22_events) C++17
30 / 100
 96 ms 28488 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], crr[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;
        crr[i] = v2[i].second.second;
    }
    // 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 j = 1; j < LOGN; ++j)
    {
        for (int i = 0; i < n; ++i)
        {
            if (j == 1)
                up[i][j] = up[par[i]][j - 1];
            else
                up[i][j] = up[up[i][j - 1]][j - 1];
            // 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--;
        int ogs = brr[s], oge = brr[e];
        int sl = v2[ogs].second.first, sr = v2[ogs].first;
        int el = v2[oge].second.first, er = v2[oge].first;
        if (ogs > oge)
        {
            if (sr >= el && sr <= er)
            {
                cout << 1 << endl;
                continue;
            }
            else
            {
                cout << "impossible" << endl;
                continue;
            }
        }
        int curr = oge;
        int ans = 0;
        int mn = sr;
        for (int i = LOGN - 1; i >= 0; --i)
        {
            if (v2[up[curr][i]].first > mn)
            {
                ans += (1 << i);
                curr = up[curr][i];
            }
        }
        if (v1[crr[curr]].first > mn)
        {
            ans++;
            curr = up[curr][0];
        }
        ans++;
        curr = up[curr][0];
        if (v1[crr[curr]].first > mn)
        {
            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;
}

Compilation message

events.cpp: In function 'void solve()':
events.cpp:167:13: warning: unused variable 'sl' [-Wunused-variable]
  167 |         int sl = v2[ogs].second.first, sr = v2[ogs].first;
      |             ^~

Subtask #1
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 344 KB Output is correct
2 Correct 70 ms 27972 KB Output is correct
3 Correct 73 ms 27856 KB Output is correct
4 Correct 79 ms 27968 KB Output is correct
5 Correct 79 ms 27908 KB Output is correct
6 Correct 74 ms 27976 KB Output is correct
7 Correct 75 ms 27880 KB Output is correct
8 Correct 65 ms 28484 KB Output is correct
9 Correct 63 ms 28292 KB Output is correct
10 Correct 87 ms 28184 KB Output is correct
11 Correct 79 ms 28228 KB Output is correct
12 Correct 62 ms 28488 KB Output is correct

Subtask #2
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 348 KB Output is correct
2 Correct 0 ms 348 KB Output is correct
3 Correct 1 ms 604 KB Output is correct
4 Correct 1 ms 604 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 0 ms 348 KB Output is correct
2 Correct 0 ms 348 KB Output is correct
3 Correct 1 ms 604 KB Output is correct
4 Correct 1 ms 604 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 0 ms 348 KB Output is correct
2 Correct 0 ms 348 KB Output is correct
3 Correct 1 ms 604 KB Output is correct
4 Correct 1 ms 604 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 72 ms 27976 KB Output is correct
2 Correct 80 ms 27772 KB Output is correct
3 Correct 84 ms 27736 KB Output is correct
4 Correct 63 ms 28488 KB Output is correct
5 Correct 96 ms 28228 KB Output is correct
6 Correct 96 ms 27992 KB Output is correct
7 Correct 95 ms 27972 KB Output is correct
8 Correct 89 ms 28104 KB Output is correct
9 Correct 50 ms 27192 KB Output is correct
10 Correct 77 ms 27720 KB Output is correct
11 Correct 93 ms 27468 KB Output is correct
12 Correct 76 ms 27712 KB Output is correct

Subtask #6
0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 344 KB Output is correct
2 Correct 70 ms 27972 KB Output is correct
3 Correct 73 ms 27856 KB Output is correct
4 Correct 79 ms 27968 KB Output is correct
5 Correct 79 ms 27908 KB Output is correct
6 Correct 74 ms 27976 KB Output is correct
7 Correct 75 ms 27880 KB Output is correct
8 Correct 65 ms 28484 KB Output is correct
9 Correct 63 ms 28292 KB Output is correct
10 Correct 87 ms 28184 KB Output is correct
11 Correct 79 ms 28228 KB Output is correct
12 Correct 62 ms 28488 KB Output is correct
13 Correct 0 ms 348 KB Output is correct
14 Correct 0 ms 348 KB Output is correct
15 Correct 1 ms 604 KB Output is correct
16 Correct 1 ms 604 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 -