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Submission #769224

# Submission time Handle Problem Language Result Execution time Memory
769224 2023-06-29T10:14:00 Z danikoynov Cat Exercise (JOI23_ho_t4) C++14
31 / 100
 96 ms 1080 KB 
#include<bits/stdc++.h>
#define endl '\n'

using namespace std;
typedef long long ll;

void speed()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);
}

const int maxn = 5010;

int n, a[maxn], used[maxn], dp[maxn], pos[maxn];
vector < int > adj[maxn];

int rec(int val)
{
    if (used[val])
        return dp[val];
    used[val] = 1;
    int left = 0, right = n + 1;
    for (int i = n; i > val; i --)
    {
        if (pos[i] > pos[val])
        {
            right = min(right, pos[i]);
        }
        else
        {
            left = max(left, pos[i]);
        }
    }

    int mx = -1;
    for (int i = pos[val] + 1; i < right; i ++)
    {
        if (a[i] > mx)
        {
            mx = a[i];
            dp[val] = max(dp[val], i - pos[val] + rec(a[i]));
        }
    }
    mx = -1;
    for (int i = pos[val] - 1; i > left; i --)
    {
        if (a[i] > mx)
        {
            mx = a[i];
            dp[val] = max(dp[val], pos[val] - i + rec(a[i]));
        }
    }
    return dp[val];
}

int dfs(int v, int p, int mx, int dis, int val)
{
    if (mx > val)
        return 0;

    int ans = 0;
    if (a[v] == mx)
        ans = max(ans, dis + dp[v]);

    for (int u : adj[v])
    {
        if (u == p)
            continue;
        ans = max(ans, dfs(u, v, max(mx, a[u]), dis + 1, val));

    }

    return ans;
}

int bef[maxn], aft[maxn];

pair < int, int > tree[4 * maxn];

void build_tree(int root, int left, int right)
{
    if (left == right)
    {
        tree[root] = {a[left], left};
        return;
    }

    int mid = (left + right) / 2;
    build_tree(root * 2, left, mid);
    build_tree(root * 2 + 1, mid + 1, right);

    tree[root] = max(tree[root * 2], tree[root * 2 + 1]);
}

pair < int, int > query(int root, int left, int right, int qleft, int qright)
{
    if (left > qright || right < qleft)
        return {-1, -1};

    if (left >= qleft && right <= qright)
        return tree[root];

    int mid = (left + right) / 2;
    return max(query(root * 2, left, mid, qleft, qright),
               query(root * 2 + 1, mid + 1, right, qleft, qright));
}

void solve()
{
    cin >> n;
    for (int i = 1; i <= n; i ++)
    {
        cin >> a[i];
        pos[a[i]] = i;
    }


    for (int i = 1; i < n; i ++)
    {
        int v, u;
        cin >> v >> u;
        adj[v].push_back(u);
        adj[u].push_back(v);
    }


    if (n <= 5000)
    {
    for (int i = 1; i <= n; i ++)
    {
        int v = pos[i];
        for (int u : adj[v])
        {
            dp[v] = max(dp[v], dfs(u, v, a[u], 1, a[v]));
        }
        ///cout << v << " : " << dp[v] << endl;
    }


    cout << dp[pos[n]] << endl;
    }
    else
    {
        stack < int > st;
        for (int i = 1; i <= n; i ++)
        {
            while(!st.empty() && a[st.top()] < a[i])
                st.pop();

            if (!st.empty())
                bef[i] = st.top();
            ///cout << "stack " << i << " " << st.top() << endl;
            st.push(i);
        }

        while(!st.empty())
            st.pop();

        for (int i = n; i > 0; i --)
        {
            while(!st.empty() && a[st.top()] < a[i])
                st.pop();
            if (!st.empty())
                aft[i] = st.top();
            else
                aft[i] = n + 1;
            st.push(i);
        }
        build_tree(1, 1, n);
        set < int > to_right, to_left;
        set < int > :: iterator it, pt;
        for (int i = 1; i <= n; i ++)
        {
            int v = pos[i];
            ///cout << "now " << v << " " << bef[v] << " " <<aft[v] << endl;
            pair < int, int > lf = query(1, 1, n, bef[v] + 1, v - 1);
            pair < int, int > rf = query(1, 1, n, v + 1, aft[v] - 1);
            ///cout << v << " " << lf.second << " " << rf.second << endl;
            if (lf.first != -1)
                dp[v] = max(dp[v], dp[lf.first] + v - lf.second);
            if (rf.first != -1)
                dp[v] = max(dp[v], dp[rf.first] + rf.second - v);

        }
        cout << dp[pos[n]] << endl;
    }



}

int main()
{
    solve();
    return 0;
}

Subtask #1
7.0 / 7.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 340 KB Output is correct
2 Correct 1 ms 340 KB Output is correct
3 Correct 1 ms 340 KB Output is correct
4 Correct 1 ms 340 KB Output is correct
5 Correct 1 ms 424 KB Output is correct
6 Correct 1 ms 340 KB Output is correct
7 Correct 1 ms 340 KB Output is correct
8 Correct 1 ms 432 KB Output is correct
9 Correct 1 ms 340 KB Output is correct
10 Correct 1 ms 428 KB Output is correct

Subtask #2
7.0 / 7.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 340 KB Output is correct
2 Correct 1 ms 340 KB Output is correct
3 Correct 1 ms 340 KB Output is correct
4 Correct 1 ms 340 KB Output is correct
5 Correct 1 ms 424 KB Output is correct
6 Correct 1 ms 340 KB Output is correct
7 Correct 1 ms 340 KB Output is correct
8 Correct 1 ms 432 KB Output is correct
9 Correct 1 ms 340 KB Output is correct
10 Correct 1 ms 428 KB Output is correct
11 Correct 1 ms 340 KB Output is correct
12 Correct 1 ms 468 KB Output is correct
13 Correct 1 ms 468 KB Output is correct
14 Correct 1 ms 340 KB Output is correct
15 Correct 1 ms 340 KB Output is correct
16 Correct 1 ms 468 KB Output is correct
17 Correct 1 ms 340 KB Output is correct

Subtask #3
7.0 / 7.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 340 KB Output is correct
2 Correct 1 ms 340 KB Output is correct
3 Correct 1 ms 340 KB Output is correct
4 Correct 1 ms 340 KB Output is correct
5 Correct 1 ms 424 KB Output is correct
6 Correct 1 ms 340 KB Output is correct
7 Correct 1 ms 340 KB Output is correct
8 Correct 1 ms 432 KB Output is correct
9 Correct 1 ms 340 KB Output is correct
10 Correct 1 ms 428 KB Output is correct
11 Correct 1 ms 340 KB Output is correct
12 Correct 1 ms 468 KB Output is correct
13 Correct 1 ms 468 KB Output is correct
14 Correct 1 ms 340 KB Output is correct
15 Correct 1 ms 340 KB Output is correct
16 Correct 1 ms 468 KB Output is correct
17 Correct 1 ms 340 KB Output is correct
18 Correct 90 ms 1080 KB Output is correct
19 Correct 83 ms 964 KB Output is correct
20 Correct 96 ms 1048 KB Output is correct
21 Correct 4 ms 1032 KB Output is correct
22 Correct 5 ms 940 KB Output is correct
23 Correct 4 ms 852 KB Output is correct
24 Correct 4 ms 852 KB Output is correct

Subtask #4
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 340 KB Output is correct
2 Correct 1 ms 340 KB Output is correct
3 Correct 1 ms 340 KB Output is correct
4 Correct 1 ms 340 KB Output is correct
5 Correct 1 ms 424 KB Output is correct
6 Correct 1 ms 340 KB Output is correct
7 Correct 1 ms 340 KB Output is correct
8 Correct 1 ms 432 KB Output is correct
9 Correct 1 ms 340 KB Output is correct
10 Correct 1 ms 428 KB Output is correct
11 Correct 1 ms 340 KB Output is correct
12 Correct 1 ms 468 KB Output is correct
13 Correct 1 ms 468 KB Output is correct
14 Correct 1 ms 340 KB Output is correct
15 Correct 1 ms 340 KB Output is correct
16 Correct 1 ms 468 KB Output is correct
17 Correct 1 ms 340 KB Output is correct
18 Correct 90 ms 1080 KB Output is correct
19 Correct 83 ms 964 KB Output is correct
20 Correct 96 ms 1048 KB Output is correct
21 Correct 4 ms 1032 KB Output is correct
22 Correct 5 ms 940 KB Output is correct
23 Correct 4 ms 852 KB Output is correct
24 Correct 4 ms 852 KB Output is correct
25 Correct 1 ms 340 KB Output is correct
26 Correct 85 ms 1016 KB Output is correct
27 Correct 92 ms 864 KB Output is correct
28 Correct 87 ms 932 KB Output is correct
29 Correct 86 ms 928 KB Output is correct
30 Correct 12 ms 724 KB Output is correct
31 Correct 13 ms 696 KB Output is correct
32 Correct 10 ms 596 KB Output is correct
33 Correct 12 ms 596 KB Output is correct

Subtask #5
0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 340 KB Output is correct
2 Correct 1 ms 340 KB Output is correct
3 Correct 1 ms 340 KB Output is correct
4 Correct 1 ms 340 KB Output is correct
5 Correct 1 ms 424 KB Output is correct
6 Correct 1 ms 340 KB Output is correct
7 Correct 1 ms 340 KB Output is correct
8 Correct 1 ms 432 KB Output is correct
9 Correct 1 ms 340 KB Output is correct
10 Correct 1 ms 428 KB Output is correct
11 Correct 1 ms 340 KB Output is correct
12 Correct 1 ms 468 KB Output is correct
13 Correct 1 ms 468 KB Output is correct
14 Correct 1 ms 340 KB Output is correct
15 Correct 1 ms 340 KB Output is correct
16 Correct 1 ms 468 KB Output is correct
17 Correct 1 ms 340 KB Output is correct
18 Correct 90 ms 1080 KB Output is correct
19 Correct 83 ms 964 KB Output is correct
20 Correct 96 ms 1048 KB Output is correct
21 Correct 4 ms 1032 KB Output is correct
22 Correct 5 ms 940 KB Output is correct
23 Correct 4 ms 852 KB Output is correct
24 Correct 4 ms 852 KB Output is correct
25 Runtime error 1 ms 596 KB Execution killed with signal 11
26 Halted 0 ms 0 KB -

Subtask #6
0 / 23.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 340 KB Output is correct
2 Correct 1 ms 428 KB Output is correct
3 Runtime error 1 ms 724 KB Execution killed with signal 11
4 Halted 0 ms 0 KB -

Subtask #7
0 / 26.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 340 KB Output is correct
2 Correct 1 ms 340 KB Output is correct
3 Correct 1 ms 340 KB Output is correct
4 Correct 1 ms 340 KB Output is correct
5 Correct 1 ms 424 KB Output is correct
6 Correct 1 ms 340 KB Output is correct
7 Correct 1 ms 340 KB Output is correct
8 Correct 1 ms 432 KB Output is correct
9 Correct 1 ms 340 KB Output is correct
10 Correct 1 ms 428 KB Output is correct
11 Correct 1 ms 340 KB Output is correct
12 Correct 1 ms 468 KB Output is correct
13 Correct 1 ms 468 KB Output is correct
14 Correct 1 ms 340 KB Output is correct
15 Correct 1 ms 340 KB Output is correct
16 Correct 1 ms 468 KB Output is correct
17 Correct 1 ms 340 KB Output is correct
18 Correct 90 ms 1080 KB Output is correct
19 Correct 83 ms 964 KB Output is correct
20 Correct 96 ms 1048 KB Output is correct
21 Correct 4 ms 1032 KB Output is correct
22 Correct 5 ms 940 KB Output is correct
23 Correct 4 ms 852 KB Output is correct
24 Correct 4 ms 852 KB Output is correct
25 Correct 1 ms 340 KB Output is correct
26 Correct 85 ms 1016 KB Output is correct
27 Correct 92 ms 864 KB Output is correct
28 Correct 87 ms 932 KB Output is correct
29 Correct 86 ms 928 KB Output is correct
30 Correct 12 ms 724 KB Output is correct
31 Correct 13 ms 696 KB Output is correct
32 Correct 10 ms 596 KB Output is correct
33 Correct 12 ms 596 KB Output is correct
34 Runtime error 1 ms 596 KB Execution killed with signal 11
35 Halted 0 ms 0 KB -