Submission #1027177

#	Time	Username	Problem	Language	Result	Execution time	Memory
1027177		huutuan	Friend (IOI14_friend)	C++14	100 / 100	25 ms	8196 KiB

friend

#include "friend.h"

#include <bits/stdc++.h>

using namespace std;

const int N=1e5+10, inf=1e9;
int a[N], f[N][2];
vector<pair<int, int>> g[N];

void dfs(int u){
   int ff[2][2]{{0, -inf}, {-inf, -inf}}, gg[2][2]{{-inf, -inf}, {-inf, -inf}};
   for (auto &e:g[u]){
      int v=e.first, w=e.second;
      dfs(v);
      for (int i=0; i<2; ++i) for (int j=0; j<2; ++j){
         gg[i][j]=max(gg[i][j], ff[i][j]+f[v][0]);
         if (w==0) gg[1][j]=max(gg[1][j], ff[i][j]+f[v][1]);
         if (w==1 && i==0) gg[i][1]=max(gg[i][1], ff[i][j]+f[v][1]);
         if (w==2 && i==0) gg[1][1]=max(gg[1][1], ff[i][j]+f[v][1]);
      }
      for (int i=0; i<2; ++i) for (int j=0; j<2; ++j) ff[i][j]=gg[i][j], gg[i][j]=-inf;
   }
   f[u][0]=max(ff[0][0], ff[1][0]);
   f[u][1]=max(ff[0][1], ff[1][1]);
   f[u][1]=max(f[u][1], max(ff[0][0], ff[0][1])+a[u]);
}

// Find out best sample
int findSample(int n,int confidence[],int host[],int protocol[]){
   for (int i=0; i<n; ++i) a[i]=confidence[i];
   for (int i=1; i<n; ++i){
      g[host[i]].emplace_back(i, protocol[i]);
   }
   dfs(0);
   return max(f[0][0], f[0][1]);
}

• Subtask 1: 11 / 11
• Subtask 2: 8 / 8
• Subtask 3: 8 / 8
• Subtask 4: 19 / 19
• Subtask 5: 23 / 23
• Subtask 6: 31 / 31