Submission #722566

#	Time	Username	Problem	Language	Result	Execution time	Memory
722566		stevancv	Beads and wires (APIO14_beads)	C++14	0 / 100	3 ms	5028 KiB

beads

#include <bits/stdc++.h>
#define ll long long
#define ld long double
#define sp ' '
#define en '\n'
#define smin(a, b) a = min(a, b)
#define smax(a, b) a = max(a, b)
using namespace std;
const int N = 2e5 + 2;
const int inf = 1e9;
vector<pair<int, int>> g[N];
int dp[N][2];
void Dfs(int s, int e, int val) {
    vector<int> all;
    int sum = 0;
    for (auto z : g[s]) {
        int u = z.first; int v = z.second;
        if (u == e) continue;
        Dfs(u, s, v);
        sum += max(dp[u][0], dp[u][1]);
        all.push_back(v + dp[u][0] - max(dp[u][0], dp[u][1]));
    }
    sort(all.rbegin(), all.rend());
    dp[s][0] = sum;
    if (all.size() > 0) dp[s][1] = sum + all[0] + val;
    if (all.size() > 1) smax(dp[s][0], sum + all[0] + all[1]);
    if (all.size() == 0) dp[s][1] = -inf;
}
int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    int n; cin >> n;
    for (int i = 0; i < n - 1; i++) {
        int u, v, w;
        cin >> u >> v >> w;
        g[u].push_back({v, w});
        g[v].push_back({u, w});
    }
    Dfs(1, 0, 0);
    cout << dp[1][0] << en;
    return 0;
}

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