一直超时四十分求助谢谢各位！

#include<stack>
#include<cstdio>
#include<cctype>
#include<cstring>
#include<algorithm>
using namespace std;
const int N=105,M=505;
struct edge{
	int Next,to;
}e[N];
int n,m,col,tot,Head[N],val[N],cost[N],W[N],V[N],color[N],a[N],dfn[N],low[N],f[N][M];
bool flag[N],vis[N];
inline int read(){
	int k=0;char ch=getchar();
	while (!isdigit(ch)) ch=getchar();
	while (isdigit(ch)){
		k=(k<<1)+(k<<3)+(ch&15);
		ch=getchar();
	}
	return k;
}
inline void add(int u,int v){
	e[++tot].Next=Head[u];
	e[tot].to=v;
	Head[u]=tot;
}
stack<int> s;
int tim=0;
inline void Tarjan(int u){
	dfn[u]=low[u]=++tim;
	s.push(u);
	for (int i=Head[u];~i;i=e[i].Next){
		int v=e[i].to;
		if (!dfn[v]){
			Tarjan(v);
			low[u]=min(low[u],low[v]);
		}else if (!color[v]) low[u]=min(low[u],dfn[v]);
	}
	if (low[u]==dfn[u]){
		color[u]=++col;
		int i=s.top();
		while (i!=u){
			color[i]=col;
			V[col]+=val[i];
			W[col]+=cost[i];
			s.pop();
			i=s.top();
		}
		V[col]+=val[u];
		W[col]+=cost[u];
		s.pop();
	}
}
inline void dfs(int u){
	if (vis[u]) return;
	vis[u]=1;
	for (int i=W[u];i<=m;i++) f[u][i]=V[u];
	for (int i=Head[u];~i;i=e[i].Next){
		int v=e[i].to;
		dfs(v);
		for (int j=m-W[u];~j;j--)
			for (int k=0;k<=j;k++)
				f[u][j+W[u]]=max(f[u][j+W[u]],f[v][k]+f[u][j+W[u]-k]);
	}
}
int main(){
	memset(Head,-1,sizeof(Head));
	n=read();m=read();
	for (int i=1;i<=n;i++) cost[i]=read();
	for (int i=1;i<=n;i++) val[i]=read();
	for (int i=1;i<=n;i++){
		a[i]=read();
		if (a[i]) add(a[i],i);
	}
	for (int i=1;i<=n;i++) if (!dfn[i]) Tarjan(i);
	memset(Head,-1,sizeof(Head));
	memset(e,0,sizeof(e));
	tot=0;
	memset(flag,1,sizeof(flag));
	for (int i=1;i<=n;i++){
		if (color[a[i]]!=color[i]){
			add(color[a[i]],color[i]);
			flag[color[i]]=0;
		}
	}
	for (int i=1;i<=col;i++) if (flag[i]) add(0,i);
	dfs(0);
	printf("%d\n",f[0][m]);
	return 0;
}