贪心，二叉树搜索，ZOJ(2315)

题目链接：http://acm.zju.edu.cn/onlinejudge/showProblem.do?problemId=1315

解题报告：

#include <stdio.h>
#include <string.h>

struct Point
{
    int pr;
    int vis;
} points[500000+5];

int ans[500000+5];
int n;

int main()
{
    int t;
    scanf("%d",&t);
    while(t--)
    {
        scanf("%d",&n);

        int sum=0;
        memset(points,0,sizeof(points));

        for(int i=2; i<=n; i++)
            scanf("%d",&points[i].pr);

        for(int i=n; i>1; i--) ///从下往上扫
        {
            if(points[i].vis==0&&points[points[i].pr].vis==0)
            {
                points[i].vis=1;
                points[points[i].pr].vis=1;
                ans[sum++]=i;
            }
        }

        printf("%d
",sum*1000);

        for(int i=sum-1; i>=0; i--)
        {
            if(i==sum-1) printf("%d",ans[i]);
            else printf(" %d",ans[i]);
        }
        puts("");
    }
    return 0;
}