# | Submission time | Handle | Problem | Language | Result | Execution time | Memory |
---|---|---|---|---|---|---|---|
372469 | 2021-02-28T09:40:40 Z | two_sides | Dreaming (IOI13_dreaming) | C++17 | 0 ms | 0 KB |
#include "dreaming.h" #include <bits/stdc++.h> using namespace std; const int N = 100005; vector <pair <int, int>> adj[N]; int par[N], dis[N]; queue <int> que; void BFS(int u, int &diam, int &dist) { int far = u; diam = 0; que.push(u); dis[u] = 0; par[u] = -1; while (que.size()) { u = que.front(); que.pop(); if (dis[u] > diam) { diam = dis[u]; far = u; } for (auto e : adj[u]) { int v, w; tie(v, w) = e; if (v != par[u]) { dis[v] = dis[u] + w; par[v] = u; que.push(v); } } } que.push(u = far); diam = dis[u] = 0; par[u] = -1; while (que.size()) { u = que.front(); que.pop(); if (dis[u] > diam) { diam = dis[u]; far = u; } for (auto e : adj[u]) { int v, w; tie(v, w) = e; if (v != par[u]) { dis[v] = dis[u] + w; par[v] = u; que.push(v); } } } dist = INT_MAX; u = far; while (u >= 0) { dist = min(dist, max (dis[u], dis[far] - dis[u])); u = par[u]; } } int travelTime(int n, int m, int l, vector <int> a, vector <int> b, vector <int> t) { for (int i = 0; i < m; i++) { adj[a[i]].emplace_back(b[i], t[i]); adj[b[i]].emplace_back(a[i], t[i]); } memset(dis, -1, sizeof dis); vector <int> tmp; int res = 0; for (int i = 0; i < n; i++) if (dis[i] < 0) { int diam, dist; BFS(i, diam, dist); res = max(res, diam); tmp.push_back(dist); } sort(tmp.begin(), tmp.end()); for (int i = 0; i + 1 < n - m; i++) tmp[i] += l; sort(tmp.begin(), tmp.end()); if (n - m > 1) res = max(res, tmp[n - m - 1] + tmp[n - m - 2]); return res; }