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Submission #895846

# Submission time Handle Problem Language Result Execution time Memory
895846 2023-12-30T22:25:10 Z tvladm2009 Exam (eJOI20_exam) C++17
100 / 100
 78 ms 123992 KB 
#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
const int N = 5e3 + 7;
const int M = 1e5 + 7;
int a[M], b[M];
bool ok[N][N];
int dp[N][N];
int t[2 * M];
int n;

void build_tree() {
    for (int i = 0; i < n; ++i) t[i + n] = a[i];
    for (int i = n - 1; i > 0; --i) t[i] = max(t[2 * i], t[2 * i + 1]);
}

int get_max(int l, int r) {
    l += n, r += n;
    int res = 0;
    while (l < r) {
        if (l & 1) res = max(res, t[l++]);
        if (r & 1) res = max(res, t[--r]);
        l >>= 1, r >>= 1;
    }
    return res;
}

void subtask2() {
    vector<int> A(n + 1), B(n + 1);
    for (int i = 1; i <= n; ++i) {
        A[i] = a[i - 1];
        B[i] = b[i - 1];
    }
    vector<int> l(n + 1), r(n + 1);
    vector<int> stk;
    for (int i = 1; i <= n; ++i) {
        while (!stk.empty() && A[i] >= A[stk.back()]) {
            stk.pop_back();
        }
        if (stk.empty()) l[i] = 1;
        else l[i] = stk.back() + 1;
        stk.push_back(i);
    }
    stk.clear();
    for (int i = n; i >= 1; --i) {
        while (!stk.empty() && A[i] >= A[stk.back()]) {
            stk.pop_back();
        }
        if (stk.empty()) r[i] = n;
        else r[i] = stk.back() - 1;
        stk.push_back(i);
    }
    vector<int> mars(n + 10, 0);
    int want = B[1];
    for (int i = 1; i <= n; ++i) {
        if (A[i] == want) {
            ++mars[l[i]];
            --mars[r[i] + 1];
        }
    }
    int ans = 0;
    for (int i = 1; i <= n; ++i) {
        mars[i] += mars[i - 1];
        if (mars[i] > 0) {
            ++ans;
        }
    }
    cout << ans << "\n";
}

int find_lis(vector<int> arr) {
    vector<int> last;
    last.push_back(0);
    for (int x : arr) {
        if (last.back() <= x) {
            last.push_back(x);
        } else {
            int pos = upper_bound(last.begin(), last.end(), x) - last.begin() - 1;
            last[pos + 1] = x;
        }
    }
    return last.size() - 1;
}
 
void subtask3() {
    build_tree();
    map<int, int> where;
    for (int i = 0; i < n; ++i) where[a[i]] = i;
    vector<int> arr;
    for (int i = 0; i < n; ++i) {
        if (where.count(b[i])) {
            int pos = where[b[i]];
            int l = i, r = pos;
            if (l > r) swap(l, r);
            if (get_max(l, r + 1) <= b[i]) arr.push_back(pos);
        }
    }
    cout << find_lis(arr) << endl;
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    cin >> n;
    for (int i = 0; i < n; i++) cin >> a[i];
    for (int i = 0; i < n; i++) cin >> b[i];
    bool same = 1;
    for (int i = 1; i < n; i++) same &= b[i] == b[0];
    if (same) {
        subtask2();
        return 0;
    }
    if (n > 5e3) {
        subtask3();
        return 0;
    }
    for (int i = 0; i < n; i++) {
        ok[i][i] = true;
        for (int j = i - 1; j >= 0; j--) {
            if (a[j] > a[i]) break;
            ok[j][i] = true;
        }
        for (int j = i + 1; j < n; j++) {
            if (a[j] > a[i]) break;
            ok[j][i] = true;
        }
    }
    for (int i = 0; i < n; i++) {
        if (ok[0][i] && b[0] == a[i]) {
            dp[0][i] = 1;
        }
    }
    for (int i = 1; i < n; i++) {
        int mx = 0;
        for (int j = 0; j < n; j++) {
            mx = max(mx, dp[i - 1][j]);
            if (ok[i][j]) {
                dp[i][j] = mx;
                if (b[i] == a[j]) ++dp[i][j];
            }
        }
    }
    int ans = 0;
    for (int i = 0; i < n; i++) ans = max(ans, dp[n - 1][i]);
    cout << ans << endl;
    return 0;
}

Subtask #1
14.0 / 14.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 2396 KB Output is correct
2 Correct 1 ms 4444 KB Output is correct
3 Correct 1 ms 2396 KB Output is correct
4 Correct 1 ms 4440 KB Output is correct
5 Correct 1 ms 2396 KB Output is correct
6 Correct 1 ms 2396 KB Output is correct

Subtask #2
12.0 / 12.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 348 KB Output is correct
2 Correct 4 ms 940 KB Output is correct
3 Correct 12 ms 3320 KB Output is correct
4 Correct 12 ms 3076 KB Output is correct
5 Correct 19 ms 4336 KB Output is correct
6 Correct 11 ms 3416 KB Output is correct
7 Correct 12 ms 3676 KB Output is correct
8 Correct 18 ms 4432 KB Output is correct

Subtask #3
13.0 / 13.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 4444 KB Output is correct
2 Correct 2 ms 16732 KB Output is correct
3 Correct 12 ms 51724 KB Output is correct
4 Correct 49 ms 121436 KB Output is correct
5 Correct 49 ms 123476 KB Output is correct
6 Correct 54 ms 123472 KB Output is correct

Subtask #4
23.0 / 23.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 604 KB Output is correct
2 Correct 32 ms 4700 KB Output is correct
3 Correct 78 ms 8148 KB Output is correct
4 Correct 76 ms 8016 KB Output is correct
5 Correct 69 ms 9012 KB Output is correct
6 Correct 65 ms 8908 KB Output is correct
7 Correct 67 ms 8652 KB Output is correct
8 Correct 78 ms 8140 KB Output is correct
9 Correct 72 ms 8816 KB Output is correct
10 Correct 50 ms 9060 KB Output is correct

Subtask #5
16.0 / 16.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 2396 KB Output is correct
2 Correct 1 ms 4444 KB Output is correct
3 Correct 1 ms 2396 KB Output is correct
4 Correct 1 ms 4440 KB Output is correct
5 Correct 1 ms 2396 KB Output is correct
6 Correct 1 ms 2396 KB Output is correct
7 Correct 1 ms 4440 KB Output is correct
8 Correct 1 ms 4440 KB Output is correct
9 Correct 1 ms 6492 KB Output is correct
10 Correct 1 ms 6748 KB Output is correct
11 Correct 1 ms 6748 KB Output is correct
12 Correct 1 ms 6748 KB Output is correct
13 Correct 1 ms 8540 KB Output is correct
14 Correct 1 ms 8540 KB Output is correct

Subtask #6
22.0 / 22.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 2396 KB Output is correct
2 Correct 1 ms 4444 KB Output is correct
3 Correct 1 ms 2396 KB Output is correct
4 Correct 1 ms 4440 KB Output is correct
5 Correct 1 ms 2396 KB Output is correct
6 Correct 1 ms 2396 KB Output is correct
7 Correct 1 ms 4444 KB Output is correct
8 Correct 2 ms 16732 KB Output is correct
9 Correct 12 ms 51724 KB Output is correct
10 Correct 49 ms 121436 KB Output is correct
11 Correct 49 ms 123476 KB Output is correct
12 Correct 54 ms 123472 KB Output is correct
13 Correct 1 ms 4440 KB Output is correct
14 Correct 1 ms 4440 KB Output is correct
15 Correct 1 ms 6492 KB Output is correct
16 Correct 1 ms 6748 KB Output is correct
17 Correct 1 ms 6748 KB Output is correct
18 Correct 1 ms 6748 KB Output is correct
19 Correct 1 ms 8540 KB Output is correct
20 Correct 1 ms 8540 KB Output is correct
21 Correct 2 ms 6748 KB Output is correct
22 Correct 5 ms 25436 KB Output is correct
23 Correct 1 ms 604 KB Output is correct
24 Correct 63 ms 122964 KB Output is correct
25 Correct 49 ms 122960 KB Output is correct
26 Correct 39 ms 123008 KB Output is correct
27 Correct 37 ms 123992 KB Output is correct
28 Correct 38 ms 122428 KB Output is correct
29 Correct 50 ms 123684 KB Output is correct
30 Correct 60 ms 123472 KB Output is correct
31 Correct 51 ms 123480 KB Output is correct
32 Correct 45 ms 123472 KB Output is correct