Submission #702027

#TimeUsernameProblemLanguageResultExecution timeMemory
702027PCTprobabilityFriend (IOI14_friend)C++17
35 / 100
2 ms2772 KiB
#include <bits/stdc++.h>
#include "friend.h"
using namespace std;
using ll = long long;
#define pb push_back
vector<int> g[100000];
int dp[100000][2];
ll con[100000];
void dfs(int a,int b){
  for(auto e:g[a]){
    if(e==b) continue;
    dfs(e,a);
    dp[a][0]+=max(dp[e][0],dp[e][1]);
    dp[a][1]+=dp[e][0];
  }
  dp[a][1]+=con[a];
}
int findSample(int n, int confidence[], int host[], int protocol[]){
  for(int i=0;i<n;i++) con[i]=confidence[i];
  bool alltwo=true;
  for(int i=1;i<n;i++){
    if(protocol[i]!=2) alltwo=false;
  }
  bool allonezero=true;
  for(int i=1;i<n;i++){
    if(protocol[i]==2) allonezero=false;
  }
  if(alltwo){
    ll ans=0;
    for(int i=0;i<n;i++) ans=max(ans,con[i]);
    return ans;
  }
  if(allonezero){
    vector<ll> r(n);
    for(int i=0;i<n;i++) r[i]=i;
    for(int i=1;i<n;i++){
      if(protocol[i]==0){
        g[r[host[i]]].pb(i);
        g[i].pb(r[host[i]]);
      }
      if(protocol[i]==1){
        con[r[host[i]]]+=con[i];
        r[i]=r[host[i]];
      }
    }
    dfs(0,-1);
    return max(dp[0][0],dp[0][1]);
  }
  assert(n<=10);
  vector<vector<int>> a(n,vector<int>(n));
  for(int i=1;i<n;i++){
    if(protocol[i]==0){
      a[i][host[i]]=a[host[i]][i]=1;
    }
    if(protocol[i]==1){
      for(int j=0;j<n;j++){
        if(a[host[i]][j]){
          a[i][j]=a[j][i]=1;
        }
      }
    }
    if(protocol[i]==2){
      for(int j=0;j<n;j++){
        if(a[host[i]][j]){
          a[i][j]=a[j][i]=1;
        }
      }
      a[i][host[i]]=a[host[i]][i]=1;
    }
  }
  int ans=0;
  for(int i=0;i<(1<<n);i++){
    int sum=0,ok=1;
    for(int j=0;j<n;j++){
      if((i>>j)&1){
        sum+=confidence[j];
        for(int k=j+1;k<n;k++){
          if((i>>k)&1){
            if(a[j][k]) ok=0;
          }
        }
      }
    }
    ans=max(ans,sum*ok);
  }
  return ans;
}     
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