磕头了 磕头了

#include<iostream>
#include<cstdio>
#include<algorithm>
#include<cstring>
#include<stack>
#define N 105
#define M 505
using namespace std;
int n,m,val[N],wei[N],d[N],value[N],weight[N];
int head[N],nxt[N],v[N],cnt;
inline void add(int x,int y)
{
	v[++cnt]=y;
	nxt[cnt]=head[x];
	head[x]=cnt;
}
int dfn[N],low[N],c[N],num,t;
stack<int> zhan;
inline void tarjan(int x)
{
	dfn[x]=low[x]=++num;
	zhan.push(x);
	for(int i=head[x];i;i=nxt[i])
	    if(!dfn[v[i]])
	    {
	    	tarjan(v[i]);
	    	low[x]=min(low[x],low[v[i]]);
		}
		else if(!c[v[i]]) low[x]=min(low[x],dfn[v[i]]);
	if(dfn[x]==low[x])
	{
		t++;
		while(zhan.top()!=x)
		{
			c[zhan.top()]=t;
			value[t]+=val[zhan.top()];
			weight[t]+=wei[zhan.top()];
			zhan.pop();
		}
		c[zhan.top()]=t;
		value[t]+=val[zhan.top()];
		weight[t]+=wei[zhan.top()];
		zhan.pop();
	}
}
int f[N][M];
inline void dfs(int x)
{
	for(int i=head[x];i;i=nxt[i])
	{
		dfs(v[i]);
		for(int j=m+1;j>=0;j--)
		{
		    for(int k=1;k<=j;k++)
		        f[x][j]=max(f[x][j],f[x][k]+f[v[i]][j-k]);
		    //printf("f[%d][%d]=%d\n",x,j,f[x][j]);
		}//printf("==============================%d %d\n",x,v[i]);
	}
}
inline void clear()
{
	memset(head,0,sizeof(head));
	memset(nxt,0,sizeof(nxt));
	memset(v,0,sizeof(v));
	cnt=0;
}
bool vis[N][N];
int main()
{
	scanf("%d%d",&n,&m);
	for(int i=1;i<=n;i++) scanf("%d",&wei[i]);
	for(int i=1;i<=n;i++) scanf("%d",&val[i]);
	for(int i=1;i<=n;i++) scanf("%d",&d[i]),add(d[i],i);
	for(int i=1;i<=n;i++)
	    if(!dfn[i]) tarjan(i);
	//for(int i=1;i<=n;i++) printf("c[%d]=%d\n",i,c[i]);
	c[0]=0;
	clear();
	for(int i=1;i<=n;i++)
	    if(!vis[c[d[i]]][c[i]] && !vis[c[i]][c[d[i]]] && c[d[i]]!=c[i]) add(c[d[i]],c[i]),vis[c[d[i]]][c[i]]=vis[c[i]][c[d[i]]]=1;
	for(int i=0;i<=t;i++) f[i][weight[i]]=value[i];
	dfs(0);
	printf("%d\n",f[0][m+1]);
	return 0;
}