首先簡單的樹形dp求祖宗到兒子的最長距離並記錄最短距離是哪個兒子
此時對於每個點只維護了兒子到它的最短距離
還要記錄祖宗到它的最短距離這時需要再跑一遍dfs把每個點與祖宗相關的到它的最長邊搞出來
經典模型必須熟悉啊！！！！！！

#include<cstdio>
#include<cstring>
#include<algorithm>
#include<iostream>
#include<vector>
#define maxn 10005
#define LL long long
using namespace std;
LL dp[maxn][2
 
], va[maxn * 2];
int Next[maxn * 2], last[maxn * 2], edge[maxn * 2], l;
int n;
void add(int a, int b, LL Va)
{
      edge[l] = b;
      va[l] = Va;
      Next[l] = last[a];
      last[a] = l;
      l++;
}
void dfs(int pre)
{
     dp[pre][0] = dp[pre][1] = 0;
     for(int i = last[pre]; i!=-1 ; i = Next[i])
     {
         dfs(edge[i]);
         if
 
(dp[edge[i]][0] + va[i]> dp[pre][0])
         {
            dp[pre][0] = dp[edge[i]][0] + va[i];
            dp[pre][1] = edge[i];
         }
     }
}
void dfs2(int pre, LL dis, int fa)
{
     if(dis >= dp[pre][0])
     {
         dp[pre][0] = dis;
         dp[pre][1] = fa;
     }
     LL Max = dis;
     int
 
 sym = -1;
     for(int i = last[pre]; i!=-1 ; i = Next[i])
     {
         if(edge[i] != dp[pre][1])
         {
            Max = max(Max, va[i] + dp[edge[i]][0]);
            dfs2(edge[i], va[i] + dp[pre][0], pre);
         }
         else sym = i;
     }
     if(sym != -1) dfs2(dp[pre][1], Max + va[sym], pre);
}
int main()
{
    while(scanf("%d", &n)!=EOF)
    {
        l = 0;
        memset(last, -1 ,sizeof(last));
        for(int i = 2; i<= n; i++)
        {
            int a;
            LL va;
            scanf("%d %I64d", &a, &va);
            add(a, i, va);
        }
        dfs(1);
       // for(int i = 1; i<= n; i++) printf("%I64d %I64d\n",dp[i][0], dp[i][1]);
        dfs2(1, 0, 0);
        for(int i = 1; i <= n; i++) printf("%I64d\n", dp[i][0]);
    }
    return 0;
}