題意：出一顆樹，有兩種操作：
1. mark u 標記結點u
2.query u 詢問離u最近的且被標記的祖先結點是哪個
讓你輸出所有詢問的和。

思路：數據量太小，直接暴力dfs就可以了

#include<iostream>
#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<cmath>
#include<vector>
#include<set>
#include<queue>
#include
 
<string>
#include<algorithm>
#define MAXSIZE 100005
#define LL long long
using namespace std;

int vis[MAXSIZE],pre[MAXSIZE];

LL dfs(int p)
{
    if(vis[p])
        return p;
    return dfs(pre[p]);
}

int main()
{
    int n,m,num;
    LL sum;
    char op[5];
    while(scanf("
 
%d%d",&n,&m),n+m)
    {
        sum = 0;
        memset(vis,0,sizeof(vis));
        vis[1] = 1;
        for(int i=2;i<=n;i++)
        {
            scanf("%d",&num);
            pre[i] = num;
        }

        while(m--)
        {
            scanf("%s%d",op,&num);
            
 
if(op[0] == ‘Q‘)
            {
                sum += dfs(num);
            }

            else
            {
                vis[num] = 1;
            }
        }

        printf("%lld\n",sum);
    }
    return 0;
}

Aizu 2170 Marked Ancestor