Submission #1015500

#	Time	Username	Problem	Language	Result	Execution time	Memory
1015500		lalig777	Dreaming (IOI13_dreaming)	C++14	100 / 100	46 ms	15592 KiB

dreaming

#include "dreaming.h"
#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
typedef long long int ll;

vector<vector<pair<int, int>>> g;
vector<bool>used;
vector<int>ans;
vector<pair<int, int>>dp;
int res=2e9;
int maxdiam=0;

void dfs1(int u){
  used[u]=true;
  for(pair<int, int> vec:g[u]){
    int v=vec.first, c=vec.second;
    if (used[v]) continue;
    dfs1(v);
    if (dp[u].first<dp[v].first+c){
      dp[u].second=dp[u].first;
      dp[u].first=dp[v].first+c;
    }else if (dp[u].second<dp[v].first+c){
      dp[u].second=dp[v].first+c;
    }
  }return;
}

void dfs2(int u, int p, int maxi){
  int maxim=maxi;
  res=min(res, max(maxim,dp[u].first));
  maxdiam=max(maxdiam, max(maxim, dp[u].first));
  for(pair<int, int> vec:g[u]){
    int v=vec.first, c=vec.second;
    if (v==p) continue;
    if (dp[u].first==dp[v].first+c) maxi=max(maxim+c, dp[u].second+c);
    else maxi=max(maxim, dp[u].first+c);
    dfs2(v, u, maxi);
  }return;
}

int travelTime(int N, int M, int L, int A[], int B[], int T[]){
  g.resize(N);
  used.assign(N, false);
  dp.assign(N, {0, 0});
  for (int i=0; i<M; i++){
    g[A[i]].push_back({B[i], T[i]});
    g[B[i]].push_back({A[i], T[i]});
  }for (int i=0; i<N; i++){
    if (used[i]) continue;
    res=2e9;
    dfs1(i);
    dfs2(i, -1, 0);
    ans.push_back(res);
  }sort(ans.begin(), ans.end());
  reverse(ans.begin(), ans.end());
  if (ans.size()==1) return max(maxdiam, ans[0]);
  if (ans.size()==2) return max(maxdiam, ans[0]+ans[1]+L);
  return max(maxdiam, max(ans[0]+ans[1]+L, ans[1]+ans[2]+2*L));
}

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