제출 #1316139

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
1316139		kawhiet	꿈 (IOI13_dreaming)	C++20	100 / 100	55 ms	16424 KiB

dreaming

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

constexpr int inf = 1e9;

vector<bool> vis;
vector<vector<pair<int, int>>> g;

vector<int> dp1, dp2, res, nodes;

void dfs_down(int u, int p) {
	nodes.push_back(u);
	vis[u] = 1;
	for (auto [v, w] : g[u]) {
		if (v == p) continue;
		dfs_down(v, u);
		if (dp1[v] + w > dp1[u]) {
			dp2[u] = dp1[u];
			dp1[u] = dp1[v] + w;
		} else {
			dp2[u] = max(dp2[u], dp1[v] + w);
		}
	}
	res[u] = max(res[u], dp1[u]);
}

void dfs(int u, int p, int up) {
	res[u] = max(res[u], up);
	for (auto [v, w] : g[u]) {
		if (v == p) continue;
		int mx = 0;
		if (dp1[v] + w == dp1[u]) {
			mx = dp2[u];
		} else {
			mx = dp1[u];
		}
		dfs(v, u, max(up, mx) + w);
	}
}

int travelTime(int n, int m, int l, int a[], int b[], int t[]) {
	g.resize(n);
	vis.resize(n);
	dp1.resize(n);
	dp2.resize(n);
	res.resize(n);
	for (int i = 0; i < m; i++) {
		int u = a[i], v = b[i], w = t[i];
		g[u].push_back({v, w});
		g[v].push_back({u, w});
	}
	int ans = 0;
	vector<int> x;
	for (int i = 0; i < n; i++) {
		if (!vis[i]) {
			dfs_down(i, -1);
			dfs(i, -1, 0);
			int mn = inf;
			for (auto j : nodes) {
				ans = max(ans, res[j]);
				mn = min(mn, res[j]);
			}
			x.push_back(mn);
			for (auto j : nodes) {
				dp1[j] = dp2[j] = res[j] = 0;
			}
			nodes.clear();
		}
	}
	sort(x.rbegin(), x.rend());
	if (x.size() >= 2) {
		ans = max(ans, x[0] + x[1] + l);
	}
	if (x.size() >= 3) {
		ans = max(ans, x[1] + x[2] + 2 * l);
	}
	return ans;
}

• Subtask 1: 14 / 14
• Subtask 2: 10 / 10
• Subtask 3: 23 / 23
• Subtask 4: 18 / 18
• Subtask 5: 12 / 12
• Subtask 6: 23 / 23