zoj2315New Year Bonus Grant Dp

#include<iostream>
#include<cstdio>
#include<cstring>
#include<map>
#include<vector>
#include<stdlib.h>
#include<algorithm>
using namespace std;

typedef long long LL;
const int maxn = 555555;

int len ;
int head[maxn];
int dp[maxn][2];
int son[maxn];
struct Node
{
    int next;int to;
}e[maxn];

void add(int from,int to)
{
    e[len].to = to;
    e[len].next =head[from];
    head[from] = len++;
}

void gao(int x)
{
    dp[x][0] = dp[x][1] = 0;son[x] = -1;
    int sum = 0;
    for(int i = head[x];i!=-1;i=e[i].next){
        int cc=e[i].to;
        gao(cc);
        sum+=dp[cc][0];
    }
    if(x!=1)
    dp[x][1] = sum+1;
    else dp[x][1] = sum;
    for(int i =  head[x];i!=-1;i=e[i].next){
        int cc=e[i].to;
        int t  = sum - dp[cc][0]+dp[cc][1];
        if(t>dp[x][0]){
            dp[x][0] = t; son[x] = cc;
        }
    }
    if(sum>dp[x][0]) son[x] = -1,dp[x][0] = sum;
}

int ans[maxn];
int cnt;

void showpath(int x,int flag)
{
    if(flag == 1) ans[cnt++] = x;
    if(flag==0){
        for(int i = head[x];i!=-1;i=e[i].next){
            int cc=e[i].to;
            if(cc==son[x]) showpath(cc,1);
            else
            showpath(cc,0);
        }
    }
    else{
        for(int i= head[x];i!=-1;i=e[i].next){
            int cc=e[i].to;
            showpath(cc,0);
        }
    }
}

int main()
{
    int T,n,a;
    cin>>T;
    int Icase=0;
    while(T--){
        if(Icase++) printf("\n");
        cin>>n;
        cnt = 0;
        len = 0 ;
        memset(head,-1,sizeof(head));
        for(int i =2;i<=n;i++){
            scanf("%d",&a);
            add(a,i);
        }
        gao(1);
        showpath(1,0);
        printf("%d\n",1000*max(dp[1][0],dp[1][1]));
        sort(ans,ans+cnt);
        printf("%d",ans[0]);
        for(int i=1;i<cnt;i++)
            printf(" %d",ans[i]);
        cout<<endl;
    }
    return 0;
}