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Submission #383011

# Submission time Handle Problem Language Result Execution time Memory
383011 2021-03-28T17:35:59 Z valerikk Exam (eJOI20_exam) C++17
100 / 100
 239 ms 122860 KB 
#include <bits/stdc++.h>
using namespace std;

const int N = 5005;
const int M = 1e5 + 7;

int n;
int a[M], b[M];
bool ok[N][N];
int dp[N][N];
int t[2 * M];

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 solve_b_equal() {
    int B = b[0];
    vector<int> inds;
    inds.push_back(-1);
    for (int i = 0; i < n; ++i) {
        if (a[i] > B) inds.push_back(i); 
    }
    inds.push_back(n);
    int ans = 0;
    for (int i = 0; i + 1 < inds.size(); ++i) {
        bool ok = false;
        for (int j = inds[i] + 1; j < inds[i + 1]; ++j) {
            ok |= a[j] == B;
        }
        if (ok) ans += inds[i + 1] - inds[i] - 1;
    }
    cout << ans << endl;
}

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 (int)last.size() - 1;
}

void solve_a_distinct() {
    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() {
#ifdef LOCAL
    freopen("input.txt", "r", stdin);
#endif
    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];
    
    
    vector<int> A;
    for (int i = 0; i < n; ++i) A.push_back(a[i]);
    sort(A.begin(), A.end());
    bool a_distinct = true;
    for (int i = 1; i < n; ++i) a_distinct &= A[i] != A[i - 1];
    if (a_distinct) {
        solve_a_distinct();
        return 0;
    }
    
    bool b_equal = true;
    for (int i = 1; i < n; ++i) b_equal &= b[i] == b[i - 1];
    if (b_equal) {
        solve_b_equal();
        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;
}

Compilation message

exam.cpp: In function 'void solve_b_equal()':
exam.cpp:38:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   38 |     for (int i = 0; i + 1 < inds.size(); ++i) {
      |                     ~~~~~~^~~~~~~~~~~~~

Subtask #1
14.0 / 14.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 364 KB Output is correct
2 Correct 1 ms 364 KB Output is correct
3 Correct 1 ms 364 KB Output is correct
4 Correct 1 ms 492 KB Output is correct
5 Correct 1 ms 492 KB Output is correct
6 Correct 1 ms 364 KB Output is correct

Subtask #2
12.0 / 12.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 364 KB Output is correct
2 Correct 6 ms 748 KB Output is correct
3 Correct 51 ms 7148 KB Output is correct
4 Correct 16 ms 1776 KB Output is correct
5 Correct 35 ms 1776 KB Output is correct
6 Correct 19 ms 2284 KB Output is correct
7 Correct 19 ms 1776 KB Output is correct
8 Correct 34 ms 2028 KB Output is correct

Subtask #3
13.0 / 13.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 364 KB Output is correct
2 Correct 1 ms 364 KB Output is correct
3 Correct 3 ms 492 KB Output is correct
4 Correct 4 ms 748 KB Output is correct
5 Correct 4 ms 748 KB Output is correct
6 Correct 5 ms 748 KB Output is correct

Subtask #4
23.0 / 23.0

# Verdict Execution time Memory Grader output
1 Correct 6 ms 748 KB Output is correct
2 Correct 44 ms 3056 KB Output is correct
3 Correct 123 ms 7020 KB Output is correct
4 Correct 123 ms 7020 KB Output is correct
5 Correct 106 ms 7912 KB Output is correct
6 Correct 109 ms 7916 KB Output is correct
7 Correct 111 ms 7404 KB Output is correct
8 Correct 120 ms 7020 KB Output is correct
9 Correct 116 ms 8044 KB Output is correct
10 Correct 78 ms 8184 KB Output is correct

Subtask #5
16.0 / 16.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 364 KB Output is correct
2 Correct 1 ms 364 KB Output is correct
3 Correct 1 ms 364 KB Output is correct
4 Correct 1 ms 492 KB Output is correct
5 Correct 1 ms 492 KB Output is correct
6 Correct 1 ms 364 KB Output is correct
7 Correct 1 ms 492 KB Output is correct
8 Correct 1 ms 620 KB Output is correct
9 Correct 1 ms 1260 KB Output is correct
10 Correct 3 ms 2156 KB Output is correct
11 Correct 2 ms 2028 KB Output is correct
12 Correct 2 ms 2156 KB Output is correct
13 Correct 2 ms 2028 KB Output is correct
14 Correct 3 ms 2028 KB Output is correct

Subtask #6
22.0 / 22.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 364 KB Output is correct
2 Correct 1 ms 364 KB Output is correct
3 Correct 1 ms 364 KB Output is correct
4 Correct 1 ms 492 KB Output is correct
5 Correct 1 ms 492 KB Output is correct
6 Correct 1 ms 364 KB Output is correct
7 Correct 1 ms 364 KB Output is correct
8 Correct 1 ms 364 KB Output is correct
9 Correct 3 ms 492 KB Output is correct
10 Correct 4 ms 748 KB Output is correct
11 Correct 4 ms 748 KB Output is correct
12 Correct 5 ms 748 KB Output is correct
13 Correct 1 ms 492 KB Output is correct
14 Correct 1 ms 620 KB Output is correct
15 Correct 1 ms 1260 KB Output is correct
16 Correct 3 ms 2156 KB Output is correct
17 Correct 2 ms 2028 KB Output is correct
18 Correct 2 ms 2156 KB Output is correct
19 Correct 2 ms 2028 KB Output is correct
20 Correct 3 ms 2028 KB Output is correct
21 Correct 2 ms 2156 KB Output is correct
22 Correct 9 ms 12268 KB Output is correct
23 Correct 2 ms 492 KB Output is correct
24 Correct 239 ms 122860 KB Output is correct
25 Correct 110 ms 122860 KB Output is correct
26 Correct 89 ms 122860 KB Output is correct
27 Correct 84 ms 115436 KB Output is correct
28 Correct 76 ms 80748 KB Output is correct
29 Correct 202 ms 91500 KB Output is correct
30 Correct 199 ms 91500 KB Output is correct
31 Correct 196 ms 91628 KB Output is correct
32 Correct 122 ms 68844 KB Output is correct