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Submission #573638

# Submission time Handle Problem Language Result Execution time Memory
573638 2022-06-07T03:33:45 Z eecs Event Hopping (BOI22_events) C++17
25 / 100
 1500 ms 98332 KB 
#include <bits/stdc++.h>
using namespace std;

const int maxn = 100010, SZ = 300;
int n, q, b[maxn], rmq[20][maxn];
int bel[maxn], bl[maxn], br[maxn];
array<int, 2> a[maxn];
vector<int> tr[maxn];

int main() {
    ios::sync_with_stdio(0), cin.tie(0);
    cin >> n >> q;
    vector<int> V;
    for (int i = 1; i <= n; i++) {
        cin >> a[i][0] >> a[i][1], V.push_back(a[i][1]);
    }
    sort(V.begin(), V.end());
    V.resize(unique(V.begin(), V.end()) - V.begin());
    fill(b + 1, b + n + 1, n + 1);
    for (int i = 1; i <= n; i++) {
        a[i][0] = lower_bound(V.begin(), V.end(), a[i][0]) - V.begin() + 1;
        a[i][1] = lower_bound(V.begin(), V.end(), a[i][1]) - V.begin() + 1;
        b[a[i][1]] = min(b[a[i][1]], a[i][0]);
    }
    for (int i = 1; i <= n; i++) {
        br[bel[i] = (i - 1) / SZ + 1] = i;
        if (!bl[bel[i]]) bl[bel[i]] = i;
    }
    copy(b + 1, b + n + 1, rmq[0] + 1);
    for (int k = 1; k < 20; k++) {
        for (int i = 1; i + (1 << k) - 1 <= n; i++) {
            rmq[k][i] = min(rmq[k - 1][i], rmq[k - 1][i + (1 << (k - 1))]);
        }
    }
    auto qmin = [&](int l, int r) {
        int k = __lg(r - l + 1);
        return min(rmq[k][l], rmq[k][r - (1 << k) + 1]);
    };
    auto go = [&](int s, int r) {
        int lb = s + 1, rb = r, ans = 0;
        while (lb <= rb) {
            int mid = (lb + rb) / 2;
            qmin(mid, r) <= s ? lb = (ans = mid) + 1 : rb = mid - 1;
        }
        return ans;
    };
    for (int i = 1; i <= n; i++) {
        for (int lim = br[bel[i]], j = go(i, lim); j && j <= lim; j = go(j, lim)) {
            tr[i].push_back(j);
        }
    }
    while (q--) {
        int s, t, ans = 0;
        cin >> s >> t;
        if (s == t) { cout << "0\n"; continue; }
        for (s = a[s][1]; s && s < a[t][0]; ans++) {
            int nxt;
            if (bel[s] + 1 >= bel[a[t][0]] || (nxt = qmin(bl[bel[s] + 1], a[t][1])) <= s) {
                s = go(s, a[t][1]);
            } else {
                auto it = lower_bound(tr[s].begin(), tr[s].end(), nxt);
                if (it == tr[s].end()) { s = 0; break; }
                ans += it - tr[s].begin(), s = *it;
            }
        }
        if (a[t][0] <= s && s <= a[t][1]) cout << ans + 1 << "\n";
        else cout << "impossible\n";
    }
    return 0;
}

Subtask #1
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 2644 KB Output is correct
2 Execution timed out 1591 ms 98204 KB Time limit exceeded
3 Halted 0 ms 0 KB -

Subtask #2
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 2644 KB Output is correct
2 Correct 1 ms 2644 KB Output is correct
3 Correct 7 ms 3544 KB Output is correct
4 Correct 6 ms 3412 KB Output is correct
5 Correct 7 ms 3540 KB Output is correct
6 Correct 2 ms 2772 KB Output is correct
7 Correct 2 ms 2772 KB Output is correct
8 Correct 2 ms 2772 KB Output is correct
9 Correct 2 ms 2772 KB Output is correct

Subtask #3
0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 2644 KB Output is correct
2 Correct 1 ms 2644 KB Output is correct
3 Correct 7 ms 3544 KB Output is correct
4 Correct 6 ms 3412 KB Output is correct
5 Correct 7 ms 3540 KB Output is correct
6 Correct 2 ms 2772 KB Output is correct
7 Correct 2 ms 2772 KB Output is correct
8 Correct 2 ms 2772 KB Output is correct
9 Correct 2 ms 2772 KB Output is correct
10 Correct 1 ms 2644 KB Output is correct
11 Correct 1 ms 2644 KB Output is correct
12 Correct 8 ms 3508 KB Output is correct
13 Correct 9 ms 3412 KB Output is correct
14 Correct 7 ms 3540 KB Output is correct
15 Correct 2 ms 2772 KB Output is correct
16 Correct 2 ms 2772 KB Output is correct
17 Correct 3 ms 2772 KB Output is correct
18 Correct 2 ms 2772 KB Output is correct
19 Execution timed out 1584 ms 5036 KB Time limit exceeded
20 Halted 0 ms 0 KB -

Subtask #4
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 2644 KB Output is correct
2 Correct 1 ms 2644 KB Output is correct
3 Correct 7 ms 3544 KB Output is correct
4 Correct 6 ms 3412 KB Output is correct
5 Correct 7 ms 3540 KB Output is correct
6 Correct 2 ms 2772 KB Output is correct
7 Correct 2 ms 2772 KB Output is correct
8 Correct 2 ms 2772 KB Output is correct
9 Correct 2 ms 2772 KB Output is correct
10 Correct 1 ms 2644 KB Output is correct
11 Correct 2 ms 2644 KB Output is correct
12 Correct 7 ms 3540 KB Output is correct
13 Correct 6 ms 3412 KB Output is correct
14 Correct 7 ms 3580 KB Output is correct
15 Correct 2 ms 2772 KB Output is correct
16 Correct 2 ms 2772 KB Output is correct
17 Correct 2 ms 2772 KB Output is correct
18 Correct 2 ms 2772 KB Output is correct
19 Correct 507 ms 97960 KB Output is correct
20 Correct 489 ms 97972 KB Output is correct
21 Correct 54 ms 12320 KB Output is correct
22 Correct 375 ms 65924 KB Output is correct
23 Correct 52 ms 13852 KB Output is correct
24 Correct 63 ms 13900 KB Output is correct
25 Correct 25 ms 10836 KB Output is correct

Subtask #5
0 / 20.0

# Verdict Execution time Memory Grader output
1 Execution timed out 1591 ms 98332 KB Time limit exceeded
2 Halted 0 ms 0 KB -

Subtask #6
0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 2644 KB Output is correct
2 Execution timed out 1591 ms 98204 KB Time limit exceeded
3 Halted 0 ms 0 KB -