Submission #1055347

#	Time	Username	Problem	Language	Result	Execution time	Memory
1055347		GrandTiger1729	Beads and wires (APIO14_beads)	C++17	0 / 100	1 ms	348 KiB

beads

#include <bits/stdc++.h>
using namespace std;

const int INF = 2e9;
int main()
{
    cin.tie(0)->sync_with_stdio(0);
    int n;
    cin >> n;
    vector<vector<pair<int, int>>> g(n);
    for (int i = 0; i < n - 1; i++)
    {
        int u, v, w;
        cin >> u >> v >> w;
        u--, v--;
        g[u].emplace_back(v, w);
        g[v].emplace_back(u, w);
    }
    vector<bool> vis(n);
    vector<vector<int>> dp(n, vector<int>(2, -INF));
    function<void(int, int)> dfs = [&](int u, int W)
    {
        vis[u] = true;
        int tot = 0;
        vector<int> res;
        for (auto &[v, w] : g[u])
        {
            if (!vis[v])
            {
                dfs(v, w);
                tot += max(dp[v][0], dp[v][1]);
                res.push_back(dp[v][0] + w - max(dp[v][0], dp[v][1]));
            }
        }
        sort(begin(res), end(res), greater<>());
        dp[u][0] = tot;
        if (res.size() >= 2)
        {
            dp[u][0] = max(dp[u][0], tot + res[0] + res[1]);
        }
        if (res.size() >= 1)
        {
            dp[u][1] = tot + res[0] + W;
        }
    };
    dfs(0, -INF);
    int ans = dp[0][0];
    cout << ans << '\n';
    return 0;
}

• Subtask 1: 0 / 13
• Subtask 2: 0 / 15
• Subtask 3: 0 / 29
• Subtask 4: 0 / 43