제출 #1264665

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
1264665		tvgk	Cat Exercise (JOI23_ho_t4)	C++20	100 / 100	178 ms	47176 KiB

Main

#include<bits/stdc++.h>
using namespace std;
#define task "a"
#define se second
#define fi first
#define ll long long
#define ii pair<ll, ll>
const long mxN = 2e5 + 7;

int n, h[mxN], par[mxN][30], a[mxN];
ll dsu[mxN];
vector<int> w[mxN];

void DFS(int j)
{
    h[j] = h[par[j][0]] + 1;
    for (int i = 1; i <= 20; i++)
        par[j][i] = par[par[j][i - 1]][i - 1];

    for (int i : w[j])
    {
        if (h[i])
            continue;

        par[i][0] = j;
        DFS(i);
    }
}

ll LCA(int u, int v)
{
    ll res = h[u] + h[v];

    if (h[u] < h[v])
        swap(u, v);

    for (int i = 20; i >= 0; i--)
    {
        if (h[par[u][i]] >= h[v])
            u = par[u][i];
    }

    if (u == v)
        return res - h[u] * 2;

    for (int i = 20; i >= 0; i--)
    {
        if (par[u][i] != par[v][i])
        {
            u = par[u][i];
            v = par[v][i];
        }
    }

    u = par[u][0];
    return res - h[u] * 2;
}

int Find(int j)
{
    if (dsu[j] <= 0)
        return j;
    else
        return dsu[j] = Find(dsu[j]);
}

void Union(int u, int v)
{
    v = Find(v);
    dsu[u] = min(dsu[u], dsu[v] - LCA(u, v));
    dsu[v] = u;
}

int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);
    //freopen(task".INP", "r", stdin);
    //freopen(task".OUT", "w", stdout);

    cin >> n;
    for (int i = 1; i <= n; i++)
        cin >> a[i];

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

    for (int i = 1; i <= n; i++)
    {
        for (int j : w[i])
        {
            if (j < i)
                Union(i, j);
        }
    }
    cout << -dsu[n];
}

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