# | Submission time | Handle | Problem | Language | Result | Execution time | Memory |
---|---|---|---|---|---|---|---|
262249 | 2020-08-12T14:26:43 Z | eohomegrownapps | Dreaming (IOI13_dreaming) | C++14 | 0 ms | 0 KB |
#include "dreaming.h" #include <bits/stdc++.h> using namespace std; vector<vector<pair<int,int>>> adjlist; //ind,val int n; vector<bool> visited; vector<int> parent; vector<int> depth; int fdist = 0; int f_ind = 0; int INF = 1e9; void getFurthest(int ind, int par){ //cout<<ind<<' '<<par<<'\n'; visited[ind]=true; parent[ind]=par; for (auto p : adjlist[ind]){ //cout<<"proc "<<p.first<<' '<<p.second<<'\n'; if (p.first==par){continue;} depth[p.first]=depth[ind]+p.second; if (depth[p.first]>fdist){ fdist=depth[p.first]; f_ind=p.first; } getFurthest(p.first,ind); } } pair<int,int> getDiamDepth(int ind){ //cout<<"check "<<ind<<'\n'; fdist=0;f_ind=ind; parent[ind]=-1; getFurthest(ind,-1); int ftmp = f_ind; fdist=0;f_ind=ftmp; parent[ftmp]=-1;depth[ftmp]=0; getFurthest(ftmp,-1); //find min depth int cur = f_ind; int md = INF; while (cur!=-1){ md = min(md, max(depth[cur],fdist-depth[cur])); cur=parent[cur]; } //cout<<ind<<": "<<fdist<<' '<<md<<'\n'; return {fdist,md}; } int travelTime(int N, int M, int L, int A[], int B[], int T[]) { n=N; adjlist.resize(n); for (int i = 0; i<M; i++){ adjlist[A[i]].push_back({B[i],T[i]}); adjlist[B[i]].push_back({A[i],T[i]}); } visited.resize(n); parent.resize(n,-1); depth.resize(n); int mindist = -1; int maxd = -1; int smaxd = -1; int tmaxd = -1; for (int i = 0; i<n; i++){ if (visited[i]){continue;} auto pii = getDiamDepth(i); maxdist = max(maxdist, pii.first); if (pii.second>=maxd){ tmaxd=smaxd; smaxd=maxd; maxd=pii.second; } else if (pii.second>=smaxd){ tmaxd=smaxd; smaxd=pii.second; } else if (pii.second>=tmaxd){ tmaxd=pii.second; } } if (tmaxd!=-1){ maxdist=max(maxdist,tmaxd+smaxd+2*L); } if (smaxd!=-1){ maxdist=max(maxdist,maxd+smaxd+L); } return maxdist; }