Submission #141643

#	Time	Username	Problem	Language	Result	Execution time	Memory
141643		kimbj0709	Dreaming (IOI13_dreaming)	C++17	100 / 100	184 ms	20212 KiB

dreaming

#include<bits/stdc++.h>
#include "dreaming.h"
using namespace std;
typedef long long ll;
#define maxn 100005
ll ret = 0;
vector<vector<pair<ll,ll> > > adj(maxn);
vector<ll> currcomponent;
vector<ll> length1(maxn,0);
vector<ll> last(maxn,-1);
vector<ll> length2(maxn,0);
void dfs(ll node,ll parent,ll weight){
  currcomponent.push_back(node);
  length1[node] = weight;
  for(auto k:adj[node]){
    if(k.first!=parent){
      dfs(k.first,node,weight+k.second);
    }
  }
  return;
}
void dfs2(ll node,ll parent,ll weight){
  length2[node] = weight;
  for(auto k:adj[node]){
    if(k.first!=parent){
      last[k.first] = node;
      dfs2(k.first,node,weight+k.second);
    }
  }
  return;
}
ll find(ll node,ll length){
  ll currnode = node;
  ll ans = INT_MAX;
  while(last[currnode]!=-1){
    ans = min(ans,max(abs(length-length2[currnode]),length2[currnode]));
    currnode = last[currnode];
  }
  ret = max(ret,length);
  return max(length-ans,ans);
}
int travelTime(int N, int M, int L, int A[], int B[], int T[]) {
  for(ll i=0;i<M;i++){
    adj[A[i]].push_back({B[i],T[i]});
    adj[B[i]].push_back({A[i],T[i]});
  }
  vector<ll> weights;
  for(int i=0;i<N;i++){
    
    if(length1[i]==0){
      dfs(i,-1,0);
      ll currmx = 0,currnode = 0;
      if(currcomponent.size()==1){
        weights.push_back(0);
        currcomponent.clear();
        goto cont;
      }
      for(int j=0;j<currcomponent.size();j++){
        if(length1[currcomponent[j]]>currmx){
          currmx = length1[currcomponent[j]];
          currnode = currcomponent[j];
        }
      }
      dfs2(currnode,-1,0);
      currmx = 0,currnode=0;
      for(int j=0;j<currcomponent.size();j++){
        if(length2[currcomponent[j]]>currmx){
          currmx = length2[currcomponent[j]];
          currnode = currcomponent[j];
        }
      }
      weights.push_back(find(currnode,currmx));
      currcomponent.clear();
    }
    cont : ;
    
  }
  
  sort(weights.begin(),weights.end());
  if(weights.size()>=2){
    ret = max(ret,weights[weights.size()-1]+weights[weights.size()-2]+L);
  }
  if(weights.size()>=3){
    ret = max(ret,weights[weights.size()-3]+weights[weights.size()-2]+2*L);
  }
  
  return ret;

}

Compilation message (stderr)

dreaming.cpp: In function 'int travelTime(int, int, int, int*, int*, int*)':
dreaming.cpp:58:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
       for(int j=0;j<currcomponent.size();j++){
                   ~^~~~~~~~~~~~~~~~~~~~~
dreaming.cpp:66:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
       for(int j=0;j<currcomponent.size();j++){
                   ~^~~~~~~~~~~~~~~~~~~~~

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