# https://vjudge.net/problem/计蒜客-44317/origin

#include <iostream>
#include <cstdio>
#include <queue>
#include <algorithm>
#include <cmath>
#include <cstring>
#define inf 2147483647
#define N 1000010
#define p(a) putchar(a)
#define For(i,a,b) for(long long i=a;i<=b;++i)

using namespace std;
long long n,k,ans,cnt,f,x,s;
long long a[N],d[N],son[N];
bool vis[N];
struct tree{
long long id;
long long dep;
bool operator < (const tree &x) const{
return dep>x.dep;
}
}b[N];

struct node{
long long n;
node *next;
}*e[N];

void in(long long &x){
long long y=1;char c=getchar();x=0;
while(c<'0'||c>'9'){if(c=='-')y=-1;c=getchar();}
while(c<='9'&&c>='0'){ x=(x<<1)+(x<<3)+c-'0';c=getchar();}
x*=y;
}
void o(long long x){
if(x<0){p('-');x=-x;}
if(x>9)o(x/10);
p(x%10+'0');
}

void push(long long x,long long y){
node *p;
p=new node();
p->n=y;
if(e[x]==0)
e[x]=p;
else{
p->next=e[x]->next;
e[x]->next=p;
}
}

void dfs(long long x){
b[x].dep=1;
for(node *i=e[x];i;i=i->next){
if(i->n!=d[x]){
dfs(i->n);
if(b[i->n].dep+1>b[x].dep){
b[x].dep=b[i->n].dep+1;
son[x]=i->n;
}
}
}
}

bool cmp(long long x,long long y){
return x>y;
}

signed main(){
in(n);in(k);d[1]=1;
For(i,1,k) in(a[i]);
For(i,2,n){
in(x);
d[i]=++x;
push(i,x);push(x,i);
}
For(i,1,n) b[i].id=i;
dfs(1);
sort(a+1,a+n+1,cmp);
sort(b+1,b+n+1);
b[1].dep--;
For(i,1,n){
if(!vis[b[i].id]){
vis[b[i].id]=1;
ans+=a[++cnt]*b[i].dep;
s=son[b[i].id];
while(s){
vis[s]=1;
s=son[s];
}
}
}
o(ans);
return 0;
}

posted @ 2020-03-25 20:28  WeiAR  阅读(...)  评论(...编辑  收藏