Submission #548408

#	Time	Username	Problem	Language	Result	Execution time	Memory
548408		Temmie	Islands (IOI08_islands)	C++17	36 / 100	2096 ms	131072 KiB

islands

#include <bits/stdc++.h>

int n;
std::vector <std::vector <std::pair <int, long long>>> g;
std::vector <int> cc;

void dfs(int node, int c, std::vector <bool>& vis) {
	if (vis[node]) {
		return;
	}
	vis[node] = true;
	cc[node] = c;
	for (auto p : g[node]) {
		dfs(p.first, c, vis);
	}
}

std::set <int> st;
long long dfs(int node, int par, int orig) {
	if (st.count(node)) {
		return 0;
	}
	if (par != -1 && node == orig) {
		return 0;
	}
	st.insert(node);
	long long r = 0;
	for (auto p : g[node]) {
		if (p.first != par && !st.count(p.first)) {
			r = std::max(r, dfs(p.first, node, orig) + p.second);
		}
	}
	st.erase(node);
	return r;
}

int main() {
	std::ios::sync_with_stdio(0); std::cin.tie(0);
	
	std::cin >> n;
	g.resize(n);
	for (int i = 0; i < n; i++) {
		int u, w; std::cin >> u >> w; u--;
		g[u].emplace_back(i, w),
		g[i].emplace_back(u, w);
	}
	cc.resize(n, -1);
	std::vector <bool> vis(n, false);
	int cnt = 0;
	for (int i = 0; i < n; i++) {
		if (!vis[i]) {
			dfs(i, cnt++, vis);
		}
	}
	std::vector <long long> cans(cnt, 0);
	for (int i = 0; i < n; i++) {
		cans[cc[i]] = std::max(cans[cc[i]], dfs(i, -1, i));
	}
	long long ans = 0;
	for (long long x : cans) {
		ans += x;
	}
	std::cout << ans << "\n";
	
}

• Subtask 1: 33 / 33
• Subtask 2: 3 / 3
• Subtask 3: 0 / 4
• Subtask 4: 0 / 10
• Subtask 5: 0 / 10
• Subtask 6: 0 / 10
• Subtask 7: 0 / 10
• Subtask 8: 0 / 10
• Subtask 9: 0 / 10