Submission #47895

#	Time	Username	Problem	Language	Result	Execution time	Memory
47895		square1001	Beads and wires (APIO14_beads)	C++14	0 / 100	7 ms	5120 KiB

beads

#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;
struct edge {
	int to, cost;
	edge() : to(-1), cost(0) {};
	edge(int to_, int cost_) : to(to_), cost(cost_) {};
};
int n, pc[200009]; long long dp[200009][2]; vector<edge> g[200009];
void solve(int pos, int pre) {
	long long best1 = -(1LL << 60), best2 = -(1LL << 60), sum = 0;
	for (edge e : g[pos]) {
		if (e.to == pre) continue;
		pc[e.to] = e.cost;
		solve(e.to, pos);
		sum += dp[e.to][1];
		long long d = dp[e.to][0] - dp[e.to][1] + e.cost;
		if (d > best1) {
			best2 = best1;
			best1 = d;
		}
		else if (d > best2) {
			best2 = d;
		}
	}
	dp[pos][0] = max(sum, sum + best1 + best2);
	dp[pos][1] = max(dp[pos][0], pc[pos] + sum + best1);
}
int main() {
	cin.tie(0);
	ios_base::sync_with_stdio(false);
	cin >> n;
	for (int i = 0; i < n - 1; i++) {
		int a, b, c;
		cin >> a >> b >> c; a--, b--;
		g[a].push_back(edge(b, c));
		g[b].push_back(edge(a, c));
	}
	solve(0, -1);
	cout << dp[0][0] << '\n';
	return 0;
}

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