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Submission #573660

# Submission time Handle Problem Language Result Execution time Memory
573660 2022-06-07T04:18:43 Z eecs Event Hopping (BOI22_events) C++17
40 / 100
 1500 ms 249612 KB 
#include <bits/stdc++.h>
using namespace std;

const int maxn = 100010, SZ = 600;
int n, q, b[maxn], rmq[17][maxn], bel[maxn], bl[maxn], br[maxn];
int num[maxn / SZ + 5][SZ + 5], tmp[SZ + 5];
short pos[maxn][SZ + 5];
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 < 17; k++) {
        memcpy(rmq[k], rmq[k - 1], sizeof(rmq[k]));
        for (int i = (1 << (k - 1)) + 1; i <= n; i++) {
            rmq[k][i] = min(rmq[k][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 + (1 << k) - 1], rmq[k][r]);
    };
    auto go = [&](int s, int r) {
        if (b[s + 1] <= s && (r == s + 1 || qmin(s + 2, r) > s)) return s + 1;
        for (int i = __lg(r); ~i && r > s; i--) {
            if (rmq[i][r] > s) r -= 1 << i;
        }
        return r <= s ? 0 : r;
    };
    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: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 4 ms 8916 KB Output is correct
2 Correct 1314 ms 249128 KB Output is correct
3 Correct 1155 ms 249104 KB Output is correct
4 Correct 859 ms 249192 KB Output is correct
5 Execution timed out 1611 ms 249232 KB Time limit exceeded
6 Halted 0 ms 0 KB -

Subtask #2
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 8896 KB Output is correct
2 Correct 4 ms 8916 KB Output is correct
3 Correct 7 ms 11220 KB Output is correct
4 Correct 7 ms 11220 KB Output is correct
5 Correct 8 ms 11220 KB Output is correct
6 Correct 6 ms 11220 KB Output is correct
7 Correct 6 ms 11220 KB Output is correct
8 Correct 6 ms 11092 KB Output is correct
9 Correct 7 ms 11220 KB Output is correct

Subtask #3
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 8896 KB Output is correct
2 Correct 4 ms 8916 KB Output is correct
3 Correct 7 ms 11220 KB Output is correct
4 Correct 7 ms 11220 KB Output is correct
5 Correct 8 ms 11220 KB Output is correct
6 Correct 6 ms 11220 KB Output is correct
7 Correct 6 ms 11220 KB Output is correct
8 Correct 6 ms 11092 KB Output is correct
9 Correct 7 ms 11220 KB Output is correct
10 Correct 5 ms 8916 KB Output is correct
11 Correct 4 ms 8916 KB Output is correct
12 Correct 8 ms 11188 KB Output is correct
13 Correct 7 ms 11192 KB Output is correct
14 Correct 7 ms 11100 KB Output is correct
15 Correct 6 ms 11220 KB Output is correct
16 Correct 6 ms 11216 KB Output is correct
17 Correct 6 ms 11220 KB Output is correct
18 Correct 6 ms 11220 KB Output is correct
19 Correct 327 ms 21260 KB Output is correct
20 Correct 212 ms 21300 KB Output is correct
21 Correct 136 ms 21512 KB Output is correct
22 Correct 40 ms 21580 KB Output is correct
23 Correct 40 ms 21448 KB Output is correct
24 Correct 33 ms 21420 KB Output is correct
25 Correct 180 ms 21064 KB Output is correct

Subtask #4
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 8896 KB Output is correct
2 Correct 4 ms 8916 KB Output is correct
3 Correct 7 ms 11220 KB Output is correct
4 Correct 7 ms 11220 KB Output is correct
5 Correct 8 ms 11220 KB Output is correct
6 Correct 6 ms 11220 KB Output is correct
7 Correct 6 ms 11220 KB Output is correct
8 Correct 6 ms 11092 KB Output is correct
9 Correct 7 ms 11220 KB Output is correct
10 Correct 5 ms 8892 KB Output is correct
11 Correct 4 ms 8916 KB Output is correct
12 Correct 8 ms 11220 KB Output is correct
13 Correct 9 ms 11220 KB Output is correct
14 Correct 8 ms 11220 KB Output is correct
15 Correct 8 ms 11228 KB Output is correct
16 Correct 6 ms 11220 KB Output is correct
17 Correct 6 ms 11220 KB Output is correct
18 Correct 8 ms 11092 KB Output is correct
19 Correct 365 ms 248524 KB Output is correct
20 Correct 372 ms 248416 KB Output is correct
21 Correct 186 ms 248216 KB Output is correct
22 Correct 367 ms 248464 KB Output is correct
23 Correct 183 ms 248424 KB Output is correct
24 Correct 205 ms 248512 KB Output is correct
25 Correct 155 ms 248104 KB Output is correct

Subtask #5
0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 1200 ms 249104 KB Output is correct
2 Correct 1117 ms 249076 KB Output is correct
3 Correct 870 ms 249072 KB Output is correct
4 Correct 202 ms 249612 KB Output is correct
5 Correct 528 ms 249460 KB Output is correct
6 Correct 1101 ms 249268 KB Output is correct
7 Correct 1218 ms 249344 KB Output is correct
8 Correct 645 ms 249364 KB Output is correct
9 Correct 190 ms 248444 KB Output is correct
10 Execution timed out 1611 ms 248592 KB Time limit exceeded
11 Halted 0 ms 0 KB -

Subtask #6
0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 8916 KB Output is correct
2 Correct 1314 ms 249128 KB Output is correct
3 Correct 1155 ms 249104 KB Output is correct
4 Correct 859 ms 249192 KB Output is correct
5 Execution timed out 1611 ms 249232 KB Time limit exceeded
6 Halted 0 ms 0 KB -