Submission #1250638

#	Time	Username	Problem	Language	Result	Execution time	Memory
1250638		norman165	Cat Exercise (JOI23_ho_t4)	C++20	31 / 100	2097 ms	37960 KiB

Main

#include <bits/stdc++.h>

#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define int long long
#define yes() cout << "YES\n"
#define no() cout << "NO\n"

using namespace std;
using ll = long long;
using ull = unsigned long long;
using ld = long double;

const int inf = 1e18;
const int mod = 1e9 + 7;
const int maxn = 1e7 + 5e6;
const int mod1 = 998244353;
const int mod2 = 1e18 + 1;
const int mod3 = 1e9 + 9;
const int mod4 = 333333333;
const int mod5 = 200000;
const int mod6 = 10007;
const int k = 300;
const int w = 1e5;
const ld EPS = 1e-8;

int LOG = 30;

vector<int> a;
vector<vector<int>> g;
vector<int> used;
vector<int> dp;

struct e {
    int cost, v, dist;
};

e get(int v, int p, int d) {
    e ans = {a[v], v, d};

    for (int& u : g[v]) {
        if (u != p && !used[u]) {
            e tmp = get(u, v, d + 1);
            if (tmp.cost > ans.cost) ans = tmp;
        }
    }

    return ans;
}

void dfs(int v, int p) {
    used[v] = 1;

    for (int& u : g[v]) {
        if (u != p && !used[u]) {
            e res = get(u, v, 1);
            int best = res.v;
            dfs(best, best);
            dp[v] = max(dp[v], dp[best] + res.dist);
        }
    }
}

void solve() {
    int n;
    cin >> n;

    a.assign(n, 0);
    g.assign(n, vector<int> ());
    used.assign(n, 0);
    dp.assign(n, 0);

    for (int& i : a) cin >> i;
    for (int i = 0; i < n - 1; i++) {
        int u, v;
        cin >> u >> v;

        u--, v--;
        g[u].push_back(v), g[v].push_back(u);
    }

    int idx = -1;
    for (int i = 0; i < n; i++) if (a[i] == n) idx = i;

    dfs(idx, idx);
    cout << dp[idx] << "\n";
}

signed main() {
    // cout.precision(16);

    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    int t = 1;
    // cin >> t;

    while (t--) {
        solve();
    }
}

• 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