# | Submission time | Handle | Problem | Language | Result | Execution time | Memory |
---|---|---|---|---|---|---|---|
110260 | 2019-05-10T10:57:42 Z | icandoit | Dreaming (IOI13_dreaming) | C++14 | 0 ms | 0 KB |
#include "dreaming.h" #include <bits/stdc++.h> #define y second #define x first #define ll long long int #define pb push_back #define pii pair<int,int> using namespace std; const int N=1e5+7; vector<pair<int,int> > adj[N]; bool vis[N]; void dfs(int node,int p,int length,pii &ans){ vis[node]=1; for(auto vertice:adj[node]){ if(vertice.x==p){ continue; } dfs(vertice.x,node,length+vertice.y,ans); } if(length>ans.y){ ans.x=node; ans.y=length; } } bool fn(int s,int e,int p,vector<int> &path){ if(s==e){ return true; } for(auto v:adj[s]){ if(v.x==p)continue; if(fn(v.x,e,u,path)){ path.push_back(v); return true; } } return false; } int travelTime(int N, int M, int L, int A[], int B[], int T[]) { int n=N; int m=M; int l=L; vector<int> radius; map<pair<int,int>,int> cost; for(int i=0; i<M; i++) { int u=A[i]; int v=B[i]; int w=T[i]; adj[u].pb({v,w}); adj[v].pb({u,w}); cost[{u,v}]=cost[{v,u}]=w; } for(int i=0;i<n;i++){ if(vis[i]) continue; pii s={-1,-1}; dfs(i,-1,0,s); pii e={-1,-1}; dfs(s.first,-1,0,e); int diameter=e.y; vector<int> path; fn(s.x,e.x,path); int sz=(int)path.size(); int rad=diameter; int cur=diameter; for(int j=1;j<sz;j++){ cur-=cost[{path[j],path[j-1]}]; rad=min(rad,max(diameter-cur,cur)); } radius.push_back(rad); } int szz=(int)radius.size(); sort(radius.rbegin(),radius.rend()); int lol=radius[0]; if(szz>=2){ lol=max(lol,radius[0]+radius[1]+l); } if(szz>=3){ lol=max(lol,radius[1]+radius[2]+2*l); } return lol; }