Submission #734185

#	Time	Username	Problem	Language	Result	Execution time	Memory
734185		SanguineChameleon	Beads and wires (APIO14_beads)	C++17	0 / 100	3 ms	4948 KiB

beads

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

void just_do_it();

int main() {
	#ifdef KAMIRULEZ
		freopen("kamirulez.inp", "r", stdin);
		freopen("kamirulez.out", "w", stdout);
	#endif
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	just_do_it();
	return 0;
}

const int maxN = 2e5 + 20;
vector<pair<int, int>> adj[maxN];
int par_w[maxN];
int dp[maxN][2];

void dfs(int u, int p) {
	int tot = 0;
	vector<int> gain;
	for (auto x: adj[u]) {
		int v = x.first;
		int w = x.second;
		if (v != p) {
			par_w[v] = w;
			dfs(v, u);
			tot += max(dp[v][0], dp[v][1]);
			gain.push_back(w + dp[v][0] - max(dp[v][0], dp[v][1]));
		}
	}
	sort(gain.begin(), gain.end(), greater<>());
	dp[u][0] = max(tot, (int)gain.size() >= 2 ? tot + gain[0] + gain[1] : -1);
	dp[u][1] = max(dp[u][0], !gain.empty() ? tot + gain[0] + par_w[u] : -1);
}

void just_do_it() {
	int n;
	cin >> n;
	for (int i = 0; i < n - 1; i++) {
		int u, v, w;
		cin >> u >> v >> w;
		adj[u].emplace_back(v, w);
		adj[v].emplace_back(u, w);
	}
	dfs(1, -1);
	cout << dp[1][0];
}

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