oj.uz

Submission #1098192

# Submission time Handle Problem Language Result Execution time Memory
1098192 2024-10-09T06:09:29 Z rifat414141 Event Hopping (BOI22_events) C++17
30 / 100
 158 ms 31556 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--;
        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 (sr >= 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;
}

Compilation message

events.cpp: In function 'void solve()':
events.cpp:167:13: warning: unused variable 'sl' [-Wunused-variable]
  167 |         int sl = v2[s].second.first, sr = v2[s].first;
      |             ^~
events.cpp:114:17: warning: variable 'crr' set but not used [-Wunused-but-set-variable]
  114 |     int brr[n], crr[n];
      |                 ^~~

Subtask #1
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 348 KB Output is correct
2 Correct 82 ms 30936 KB Output is correct
3 Correct 112 ms 31064 KB Output is correct
4 Correct 100 ms 31044 KB Output is correct
5 Correct 90 ms 31032 KB Output is correct
6 Correct 92 ms 31028 KB Output is correct
7 Correct 86 ms 31008 KB Output is correct
8 Correct 79 ms 31556 KB Output is correct
9 Correct 75 ms 31476 KB Output is correct
10 Correct 112 ms 31312 KB Output is correct
11 Correct 114 ms 31428 KB Output is correct
12 Correct 101 ms 30728 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 1 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 1 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 1 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 90 ms 31032 KB Output is correct
2 Correct 92 ms 31020 KB Output is correct
3 Correct 93 ms 31056 KB Output is correct
4 Correct 73 ms 31508 KB Output is correct
5 Correct 136 ms 31332 KB Output is correct
6 Correct 115 ms 31176 KB Output is correct
7 Correct 158 ms 31184 KB Output is correct
8 Correct 95 ms 31348 KB Output is correct
9 Correct 55 ms 29256 KB Output is correct
10 Correct 82 ms 30672 KB Output is correct
11 Correct 85 ms 30648 KB Output is correct
12 Correct 133 ms 30656 KB Output is correct

Subtask #6
0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 348 KB Output is correct
2 Correct 82 ms 30936 KB Output is correct
3 Correct 112 ms 31064 KB Output is correct
4 Correct 100 ms 31044 KB Output is correct
5 Correct 90 ms 31032 KB Output is correct
6 Correct 92 ms 31028 KB Output is correct
7 Correct 86 ms 31008 KB Output is correct
8 Correct 79 ms 31556 KB Output is correct
9 Correct 75 ms 31476 KB Output is correct
10 Correct 112 ms 31312 KB Output is correct
11 Correct 114 ms 31428 KB Output is correct
12 Correct 101 ms 30728 KB Output is correct
13 Correct 0 ms 348 KB Output is correct
14 Correct 1 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 -