Submission #769136

#	Time	Username	Problem	Language	Result	Execution time	Memory
769136		danikoynov	Cat Exercise (JOI23_ho_t4)	C++14	31 / 100	94 ms	1040 KiB

Main

#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;
}
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);
    }

    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;

}

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

Compilation message (stderr)

Main.cpp: In function 'int dfs(int, int, int, int, int)':
Main.cpp:69:9: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
   69 |         if (u == p)
      |         ^~
Main.cpp:71:13: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'if'
   71 |             ans = max(ans, dfs(u, v, max(mx, a[u]), dis + 1, val));
      |             ^~~

• Subtask 1: 7 / 7
• Subtask 2: 7 / 7
• Subtask 3: 7 / 7
• Subtask 4: 10 / 10
• Subtask 5: 0 / 20
• Subtask 6: 0 / 23
• Subtask 7: 0 / 26