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Submission #573644

# Submission time Handle Problem Language Result Execution time Memory
573644 2022-06-07T03:55:35 Z eecs Event Hopping (BOI22_events) C++17
40 / 100
 1500 ms 406560 KB 
#include <bits/stdc++.h>
using namespace std;

const int maxn = 100010, SZ = 500;
int n, q, b[maxn], rmq[20][maxn], bel[maxn], bl[maxn], br[maxn];
int num[maxn / SZ + 5][SZ + 5], pos[maxn][SZ + 5], tmp[maxn];
array<int, 2> a[maxn];
vector<int> tr[maxn];

int main() {
    double start = clock();
    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 k = 1; k <= bel[n]; k++) {
        for (int i = br[k], j = br[k]; i >= bl[k]; i--) {
            for (; j >= max(bl[k], b[i]); j--) num[k][j - bl[k]] = j < i ? i : 0;
        }
    }
    for (int i = 1; i <= n; i++) {
        int k = bel[i], L = bl[k], R = br[k];
        tr[i].reserve(SZ);
        for (int j = num[k][i - L]; j && j <= R; j = num[k][j - L]) {
            tr[i].push_back(j);
        }
        for (int j = L, k = 0; j <= R; j++) {
            while (k < tr[i].size() && tr[i][k] < j) k++;
            pos[i][j - L] = k;
        }
    }
    cerr << clock() - start << endl;
    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++) {
            if (bel[s] == bel[a[t][0]]) {
                for (int i = a[t][0], j = a[t][0]; i >= s; i--) {
                    int v = i == a[t][0] ? qmin(i, a[t][1]) : b[i];
                    for (; j >= max(s, v); j--) tmp[j - s] = j < i ? i : 0;
                }
                for (int o = s; s && s < a[t][0]; ans++) {
                    s = tmp[s - o];
                }
                break;
            }
            int nxt = qmin(bl[bel[s] + 1], a[t][1]);
            if (nxt <= s) {
                s = go(s, a[t][1]);
            } else {
                if (tr[s].empty() || nxt > tr[s].back()) { s = 0; break; }
                int i = pos[s][nxt - bl[bel[s]]];
                ans += i, s = tr[s][i];
            }
        }
        if (a[t][0] <= s && s <= a[t][1]) cout << ans + 1 << "\n";
        else cout << "impossible\n";
    }
    cerr << clock() - start << endl;
    return 0;
}

Compilation message

events.cpp: In function 'int main()':
events.cpp:60:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   60 |             while (k < tr[i].size() && tr[i][k] < j) k++;
      |                    ~~^~~~~~~~~~~~~~

Subtask #1
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 2644 KB Output is correct
2 Execution timed out 1616 ms 406456 KB Time limit exceeded
3 Halted 0 ms 0 KB -

Subtask #2
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 2644 KB Output is correct
2 Correct 2 ms 2644 KB Output is correct
3 Correct 7 ms 6740 KB Output is correct
4 Correct 6 ms 6740 KB Output is correct
5 Correct 7 ms 6740 KB Output is correct
6 Correct 5 ms 6740 KB Output is correct
7 Correct 4 ms 6740 KB Output is correct
8 Correct 5 ms 6740 KB Output is correct
9 Correct 4 ms 6740 KB Output is correct

Subtask #3
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 2644 KB Output is correct
2 Correct 2 ms 2644 KB Output is correct
3 Correct 7 ms 6740 KB Output is correct
4 Correct 6 ms 6740 KB Output is correct
5 Correct 7 ms 6740 KB Output is correct
6 Correct 5 ms 6740 KB Output is correct
7 Correct 4 ms 6740 KB Output is correct
8 Correct 5 ms 6740 KB Output is correct
9 Correct 4 ms 6740 KB Output is correct
10 Correct 1 ms 2644 KB Output is correct
11 Correct 2 ms 2772 KB Output is correct
12 Correct 7 ms 6740 KB Output is correct
13 Correct 6 ms 6704 KB Output is correct
14 Correct 6 ms 6740 KB Output is correct
15 Correct 5 ms 6740 KB Output is correct
16 Correct 5 ms 6740 KB Output is correct
17 Correct 4 ms 6740 KB Output is correct
18 Correct 5 ms 6740 KB Output is correct
19 Correct 169 ms 23364 KB Output is correct
20 Correct 325 ms 23528 KB Output is correct
21 Correct 135 ms 23608 KB Output is correct
22 Correct 41 ms 23668 KB Output is correct
23 Correct 43 ms 23500 KB Output is correct
24 Correct 36 ms 23480 KB Output is correct
25 Correct 195 ms 23056 KB Output is correct

Subtask #4
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 2644 KB Output is correct
2 Correct 2 ms 2644 KB Output is correct
3 Correct 7 ms 6740 KB Output is correct
4 Correct 6 ms 6740 KB Output is correct
5 Correct 7 ms 6740 KB Output is correct
6 Correct 5 ms 6740 KB Output is correct
7 Correct 4 ms 6740 KB Output is correct
8 Correct 5 ms 6740 KB Output is correct
9 Correct 4 ms 6740 KB Output is correct
10 Correct 1 ms 2644 KB Output is correct
11 Correct 2 ms 2772 KB Output is correct
12 Correct 6 ms 6740 KB Output is correct
13 Correct 6 ms 6736 KB Output is correct
14 Correct 5 ms 6740 KB Output is correct
15 Correct 4 ms 6740 KB Output is correct
16 Correct 5 ms 6676 KB Output is correct
17 Correct 4 ms 6780 KB Output is correct
18 Correct 4 ms 6724 KB Output is correct
19 Correct 454 ms 406040 KB Output is correct
20 Correct 457 ms 406044 KB Output is correct
21 Correct 242 ms 405912 KB Output is correct
22 Correct 408 ms 406032 KB Output is correct
23 Correct 260 ms 406060 KB Output is correct
24 Correct 260 ms 406088 KB Output is correct
25 Correct 208 ms 405776 KB Output is correct

Subtask #5
0 / 20.0

# Verdict Execution time Memory Grader output
1 Execution timed out 1598 ms 406560 KB Time limit exceeded
2 Halted 0 ms 0 KB -

Subtask #6
0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 2644 KB Output is correct
2 Execution timed out 1616 ms 406456 KB Time limit exceeded
3 Halted 0 ms 0 KB -