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Submission #573646

# Submission time Handle Problem Language Result Execution time Memory
573646 2022-06-07T03:57:43 Z eecs Event Hopping (BOI22_events) C++17
40 / 100
 1500 ms 366828 KB 
#include <bits/stdc++.h>
using namespace std;

const int maxn = 100010, SZ = 600;
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() {
    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(R - i);
        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;
        }
    }
    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";
    }
    return 0;
}

Compilation message

events.cpp: In function 'int main()':
events.cpp:59:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   59 |             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 1603 ms 366828 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 6 ms 6100 KB Output is correct
4 Correct 5 ms 6100 KB Output is correct
5 Correct 5 ms 6100 KB Output is correct
6 Correct 4 ms 6100 KB Output is correct
7 Correct 4 ms 6100 KB Output is correct
8 Correct 4 ms 6100 KB Output is correct
9 Correct 3 ms 6100 KB Output is correct

Subtask #3
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 6 ms 6100 KB Output is correct
4 Correct 5 ms 6100 KB Output is correct
5 Correct 5 ms 6100 KB Output is correct
6 Correct 4 ms 6100 KB Output is correct
7 Correct 4 ms 6100 KB Output is correct
8 Correct 4 ms 6100 KB Output is correct
9 Correct 3 ms 6100 KB Output is correct
10 Correct 2 ms 2644 KB Output is correct
11 Correct 1 ms 2644 KB Output is correct
12 Correct 7 ms 6100 KB Output is correct
13 Correct 6 ms 6100 KB Output is correct
14 Correct 5 ms 6100 KB Output is correct
15 Correct 5 ms 6100 KB Output is correct
16 Correct 4 ms 6100 KB Output is correct
17 Correct 4 ms 6100 KB Output is correct
18 Correct 3 ms 6100 KB Output is correct
19 Correct 337 ms 21176 KB Output is correct
20 Correct 247 ms 21172 KB Output is correct
21 Correct 143 ms 21420 KB Output is correct
22 Correct 40 ms 21460 KB Output is correct
23 Correct 49 ms 21272 KB Output is correct
24 Correct 33 ms 21256 KB Output is correct
25 Correct 174 ms 20992 KB Output is correct

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 6 ms 6100 KB Output is correct
4 Correct 5 ms 6100 KB Output is correct
5 Correct 5 ms 6100 KB Output is correct
6 Correct 4 ms 6100 KB Output is correct
7 Correct 4 ms 6100 KB Output is correct
8 Correct 4 ms 6100 KB Output is correct
9 Correct 3 ms 6100 KB Output is correct
10 Correct 1 ms 2644 KB Output is correct
11 Correct 1 ms 2644 KB Output is correct
12 Correct 7 ms 6212 KB Output is correct
13 Correct 6 ms 6100 KB Output is correct
14 Correct 5 ms 6100 KB Output is correct
15 Correct 4 ms 6100 KB Output is correct
16 Correct 3 ms 6100 KB Output is correct
17 Correct 4 ms 6100 KB Output is correct
18 Correct 3 ms 6100 KB Output is correct
19 Correct 406 ms 366372 KB Output is correct
20 Correct 409 ms 366484 KB Output is correct
21 Correct 229 ms 366136 KB Output is correct
22 Correct 390 ms 366608 KB Output is correct
23 Correct 219 ms 366336 KB Output is correct
24 Correct 233 ms 366372 KB Output is correct
25 Correct 210 ms 366028 KB Output is correct

Subtask #5
0 / 20.0

# Verdict Execution time Memory Grader output
1 Execution timed out 1604 ms 366824 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 1603 ms 366828 KB Time limit exceeded
3 Halted 0 ms 0 KB -