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Submission #383010

# Submission time Handle Problem Language Result Execution time Memory
383010 2021-03-28T17:35:19 Z valerikk Exam (eJOI20_exam) C++17
100 / 100
 238 ms 122988 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];
    
    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;
    }
    
    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;
    }
    
    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 492 KB Output is correct
3 Correct 19 ms 1504 KB Output is correct
4 Correct 14 ms 1176 KB Output is correct
5 Correct 26 ms 1152 KB Output is correct
6 Correct 15 ms 1776 KB Output is correct
7 Correct 15 ms 1132 KB Output is correct
8 Correct 25 ms 1520 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 2 ms 492 KB Output is correct
4 Correct 4 ms 748 KB Output is correct
5 Correct 5 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 47 ms 3228 KB Output is correct
3 Correct 140 ms 8212 KB Output is correct
4 Correct 136 ms 8940 KB Output is correct
5 Correct 109 ms 9904 KB Output is correct
6 Correct 110 ms 9068 KB Output is correct
7 Correct 111 ms 9452 KB Output is correct
8 Correct 124 ms 8172 KB Output is correct
9 Correct 113 ms 9068 KB Output is correct
10 Correct 76 ms 9068 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 2 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 2 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 2 ms 492 KB Output is correct
10 Correct 4 ms 748 KB Output is correct
11 Correct 5 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 2 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 2 ms 2028 KB Output is correct
21 Correct 2 ms 2156 KB Output is correct
22 Correct 8 ms 12268 KB Output is correct
23 Correct 2 ms 364 KB Output is correct
24 Correct 238 ms 122820 KB Output is correct
25 Correct 111 ms 122988 KB Output is correct
26 Correct 90 ms 122860 KB Output is correct
27 Correct 87 ms 115436 KB Output is correct
28 Correct 75 ms 80748 KB Output is correct
29 Correct 200 ms 91500 KB Output is correct
30 Correct 208 ms 91468 KB Output is correct
31 Correct 195 ms 91628 KB Output is correct
32 Correct 118 ms 68844 KB Output is correct