Submission #1043785

#TimeUsernameProblemLanguageResultExecution timeMemory
1043785vaneaDreaming (IOI13_dreaming)C++14
100 / 100
41 ms18028 KiB
#include <bits/stdc++.h> #include "dreaming.h" using namespace std; using ll = long long; using ld = long double; const int mxN = 1e5+10; vector<array<int, 2>> adj[mxN]; bool vis[mxN]; ll ans = 0, mx_1[mxN], mx_2[mxN]; ll dfs(int node, int p) { ll mx1 = 0, mx2 = 0; vis[node] = true; for(auto [it, w] : adj[node]) { if(it == p) continue; mx2 = max(mx2, dfs(it, node)+w); if(mx2 > mx1) swap(mx1, mx2); } ans = max(ans, mx2+mx1); mx_1[node] = mx1; mx_2[node] = mx2; return mx1; } ll dfs1(int node, int p) { ll mn = mx_1[node]; vis[node] = true; for(auto [it, w] : adj[node]) { if(it == p) continue; if(mx_1[node]-w == mx_1[it]) { mx_2[it] = max(mx_2[it], mx_2[node]+w); if(mx_2[it] > mx_1[it]) swap(mx_2[it], mx_1[it]); } else { int init = mx_1[it]; mx_2[it] = max(mx_2[it], mx_1[node]+w); if(mx_2[it] > mx_1[it]) swap(mx_2[it], mx_1[it]); if(mx_2[node]-w != init) { mx_2[it] = max(mx_2[it], mx_2[node]+w); } } mn = min(mn, dfs1(it, node)); } return mn; } int travelTime(int n, int m, int l, int a[], int b[], int t[]) { for(int i = 0; i < m; i++) { adj[a[i]].push_back({b[i], t[i]}); adj[b[i]].push_back({a[i], t[i]}); } for(int i = 0; i < n; i++) { if(!vis[i]) dfs(i, -1); } if(m == n-1) return ans; memset(vis, false, sizeof vis); vector<ll> dists; for(int i = 0; i < n; i++) { if(!vis[i]) { dists.push_back(dfs1(i, -1)); } } sort(dists.rbegin(), dists.rend()); ans = max(ans, dists[0]+dists[1]+l); if(dists.size() >= 3) { ans = max(ans, dists[1]+dists[2]+l+l); } return ans; } /* int main() { int a[8] = {0,8,2,5,5,1,1,10}; int b[8] = {8,2,7,11,1,3,9,6}; int c[8] = {4,2,4,3,7,1,5,3}; cout << travelTime(12, 8, 2, a, b, c); }*/

Compilation message (stderr)

dreaming.cpp: In function 'll dfs(int, int)':
dreaming.cpp:16:14: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   16 |     for(auto [it, w] : adj[node]) {
      |              ^
dreaming.cpp: In function 'll dfs1(int, int)':
dreaming.cpp:30:14: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   30 |     for(auto [it, w] : adj[node]) {
      |              ^
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