Codeforces Round #359 (Div. 1) B. Kay and Snowflake dfs

#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <cmath>
#include<bits/stdc++.h>
using namespace std;
#define sf scanf
#define pf printf
#define mem(a,b) memset(a,b,sizeof(a));
#define rep(i,a,b) for(int i=(a);i<=(b);++i)
#define MP make_pair
#define ULL unsigned long long
#define LL   long long
#define inf 0x3f3f3f3f
#define md ((ll+rr)>>1)
#define ls (i<<1)
#define rs (ls|1)
#define eps 1e-5
#define ree freopen("in.txt","r",stdin);
#define bug pf("----------------");
#define N 300010
//2017年09月02日12:40:54

int ans
;
vector<int>G
;
int fa
;
int sz
;
void dfs(int x){
int len=G[x].size();
sz[x]=1;
ans[x]=x;
for(int i=0;i<len;++i){
int v=G[x][i]; dfs(v);
sz[x]+=sz[v];
}
for(int i=0;i<len;++i){
int v=G[x][i];
if(sz[v]*2>sz[x]){
ans[x]=ans[v];
}
}
while((sz[x]-sz[ans[x]])*2>sz[x])ans[x]=fa[ans[x]];
}
int main(){
int n;sf("%d",&n);
int q;sf("%d",&q);
rep(i,2,n){
sf("%d",&fa[i]);
G[fa[i]].push_back(i);
}
dfs(1);
while(q--){
int x;sf("%d",&x);
pf("%d\n",ans[x]);
}
}