Submission #53580

#	Time	Username	Problem	Language	Result	Execution time	Memory
53580		alenam0161	Dreaming (IOI13_dreaming)	C++17	100 / 100	230 ms	23800 KiB

dreaming

# include "dreaming.h"
#include <iostream>
#include <vector>
#include <cstdio>
#include <algorithm>
#include  <cmath>
#include <cstring>
using namespace std;
const int Mxn=1e5+7;
vector<int> g[Mxn],cost[Mxn];
bool used[Mxn];
int di[Mxn];
int cur=0;
void dfs(int v,int p){
    for(int i=0;i<g[v].size();++i){
        int to=g[v][i];
        int c=cost[v][i];
        if(to==p)continue;
        dfs(to,v);
        di[v]=max(di[v],di[to]+c);
    }
}
void go(int v,int p,int cp){
    int cs=-1;
    int e=0;
    int r=0;
    for(int i=0;i<g[v].size();++i){
        int to=g[v][i];
        int c=cost[v][i];
        if(to==p)continue;
        if(cs==-1||di[cs]+e<di[to]+c){
            if(cs!=-1){
                r=di[cs]+e;
            }
            cs=to;
            e=c;
        }
        else if(di[to]+c>r){
            r=di[to]+c;
        }
    }
    cur=min(cur,max(cp,di[v]));
   // cout<<v<<" "<<cp<<" "<<di[v]<<" "<<r<<endl;
     for(int i=0;i<g[v].size();++i){
        int to=g[v][i];
        int c=cost[v][i];
        if(to==p)continue;
        if(cs==to){
            go(to,v,max(cp,r)+c);
        }
        else{
            go(to,v,max(cp,cs==-1? 0:di[cs]+e));
        }
    }
}
void dfs_fill(int v,int p){
    used[v]=true;
    for(int i=0;i<g[v].size();++i){
        if(used[g[v][i]]==true)continue;
        dfs_fill(g[v][i],v);
    }
}
pair<int,int> get(int v,int p){
    pair<int,int> Z0=make_pair(0,v);
    for(int i=0;i<g[v].size();++i){
        int to=g[v][i];
        int c=cost[v][i];
        if(to==p)continue;
        pair<int,int> e=get(to,v);e.first+=c;
        Z0=max(Z0,e);
    }
    return Z0;
}
int travelTime (int N, int M, int L, int A[], int B[], int T[]) {
  memset(di,0,sizeof(di));
  memset(used,0,sizeof(used));
  for(int i=0;i<M;++i){
    g[A[i]].push_back(B[i]);
    g[B[i]].push_back(A[i]);
    cost[A[i]].push_back(T[i]);
    cost[B[i]].push_back(T[i]);
  }
  vector<int> z;
  int ans=0;
  for(int i=0;i<N;++i){
    if(used[i]==false){
        dfs(i,i);
        cur=1e9;
        go(i,i,0);
        int gag=get(i,i).second;
        ans=max(ans,get(gag,gag).first);
        z.push_back(cur);
        dfs_fill(i,i);
    }
  }
  sort(z.begin(),z.end());
  reverse(z.begin(),z.end());
  if(z.size()==1)ans=max(ans,z[0]);
  else if(z.size()==2){
   ans=max(ans,z[0]+L+z[1]);
  }
  else{
    ans=max(ans,max(z[0]+L+z[1],L+L+z[1]+z[2]));
  }
  return ans;
}

Compilation message (stderr)

dreaming.cpp: In function 'void dfs(int, int)':
dreaming.cpp:15:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i=0;i<g[v].size();++i){
                 ~^~~~~~~~~~~~
dreaming.cpp: In function 'void go(int, int, int)':
dreaming.cpp:27:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i=0;i<g[v].size();++i){
                 ~^~~~~~~~~~~~
dreaming.cpp:44:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
      for(int i=0;i<g[v].size();++i){
                  ~^~~~~~~~~~~~
dreaming.cpp: In function 'void dfs_fill(int, int)':
dreaming.cpp:58:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i=0;i<g[v].size();++i){
                 ~^~~~~~~~~~~~
dreaming.cpp: In function 'std::pair<int, int> get(int, int)':
dreaming.cpp:65:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i=0;i<g[v].size();++i){
                 ~^~~~~~~~~~~~

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