bzoj 2427: [HAOI2010]软件安装

额，（sb题？？）

缩了点搞呗，，（背包。。。）

#include<cstdio>
#include<algorithm>
#define N 100005
#define eps 1e-8
using namespace std;
inline int ra()
{
    int x=0,f=1; char ch=getchar();
    while (ch<'0' || ch>'9') {if (ch=='-') f=-1; ch=getchar();}
    while (ch>='0' && ch<='9') {x=x*10+ch-'0'; ch=getchar();}
    return x*f;
}
int n,m,cnt,sc,ind,top,CNT;
int v[105],w[105];
int sv[105],sw[105];
int dfn[105],low[105],belong[105];
int q[105],f[105][505],in[505];
struct edge{
    int to,next;
}e[505],E[505];
int HEAD[105],head[105];
bool inq[105];
void insert(int x, int y)
{
    e[++cnt].to=y; e[cnt].next=head[x]; head[x]=cnt;
}
void INSERT(int x, int y)
{
    in[y]=1;
    E[++CNT].to=y; E[CNT].next=HEAD[x]; HEAD[x]=CNT;
}
void tarjan(int x)
{
    int now=0;
    low[x]=dfn[x]=++ind;
    q[++top]=x; inq[x]=1;
    for (int i=head[x];i;i=e[i].next)
        if (!dfn[e[i].to])
        {
            tarjan(e[i].to);
            low[x]=min(low[x],low[e[i].to]);
        }
        else if (inq[e[i].to]) low[x]=min(low[x],dfn[e[i].to]);
    if (low[x]==dfn[x])
    {
        sc++;
        while (now!=x)
        {
            now=q[top--]; inq[now]=0;
            belong[now]=sc;
            sv[sc]+=v[now];
            sw[sc]+=w[now];
        }
    }        
}
void rebuild()
{
    for (int x=1; x<=n; x++)
        for (int i=head[x];i;i=e[i].next)
            if (belong[e[i].to]!=belong[x])
                INSERT(belong[x],belong[e[i].to]);
}
void dp(int x)
{
    for (int i=HEAD[x];i;i=E[i].next)
    {
        dp(E[i].to);
        for (int j=m-sw[x]; j>=0; j--)
            for (int k=0; k<=j; k++)
                f[x][j]=max(f[x][j],f[x][k]+f[E[i].to][j-k]);
    }
    for (int j=m; j>=0; j--)
        if (j>=sw[x]) f[x][j]=f[x][j-sw[x]]+sv[x];
        else f[x][j]=0;
}
int main()
{
    n=ra(); m=ra();
    for (int i=1; i<=n; i++) w[i]=ra();
    for (int i=1; i<=n; i++) v[i]=ra();
    for (int i=1; i<=n; i++) insert(ra(),i);
    for (int i=1; i<=n; i++)
        if (!dfn[i]) tarjan(i);
    rebuild();
    for (int i=1; i<=sc; i++)
        if (!in[i]) INSERT(sc+1,i);
    dp(sc+1);
    printf("%d
",f[sc+1][m]);
    return 0;
}