Submission #1755488

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Source Code Expand

#include<bits/stdc++.h>
#define N 100005
using namespace std;

typedef pair<int,int> P;

vector<int> G[N];
int n, par[N], dep[N], chinum[N];
priority_queue<P> q;

int dfs(int x, int d){

  dep[x] = d;
  int res = 0;
  
  for(int i=0;i<G[x].size();i++){
    int nx = G[x][i];
    res += dfs(nx, d+1);
  }
  
  if(!res) res = 1, chinum[x] = 0;
  else chinum[x] = res;
  
  return res;
}

bool used[N];
int cnt[N];

void solve(){
  
  for(int i=1;i<n;i++)
    if(chinum[i]==cnt[i]) q.push(P(dep[i], i));

  vector<P> tmp;
  int ans=0;
  
  while(!q.empty()){
    
    while(!q.empty()){
    
      P t = q.top(); q.pop();

      int node = t.second;
    
      if(!used[par[node]]&&cnt[node]==chinum[node]){
	used[par[node]]=true;
	cnt[par[node]] += cnt[node]+1;
	if(cnt[par[node]]==chinum[par[node]])
	  tmp.push_back(P(dep[par[node]], par[node]));
      } else tmp.push_back(t);

    }
    
    for(int i=0;i<tmp.size();i++) q.push(tmp[i]);
    
    memset(used,0,sizeof(used));
    
    tmp.clear();
    ans++;
  }
  
  cout<<ans<<endl;
  
}


int main(){
  
  cin>>n;
  
  for(int i=0;i<n-1;i++){
    int a;
    scanf("%d", &a);
    G[a-1].push_back(i+1);
    par[i+1] = a-1;
  }
  
  dfs(0,0);

  solve();
  
  return 0;
}

Submission Info

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:74:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d", &a);
                    ^

Judge Result