int[] ans;
    int n;
    List<Integer>[] list;
    public int[] huangen(int n, int[][] edges) {
        this.list = new List[n];
        this.ans = new int[n];
        this.n = n;
        Arrays.setAll(list,e->new LinkedList<>());
        for(int[] edge:edges){
            int y = edge[0],x= edge[1];
            list[y].add(x);
            list[x].add(y);
        }
        dfs(-1,0,0);
        reroot(-1,0);
        return ans;
    }
    void dfs(int fa,int cur,int deep){
        ans[0]+=deep;
        for(int son:list[cur]){
            if(son == fa) continue;
            dfs(cur,son,deep+1);//后续遍历
        }
    }
    void reroot(int fa, int cur){
        for(int son:list[cur]){
            if(son == fa) continue;
            ans[son] =  ans[cur] + 相关数据;
            reroot(cur,son);
        }
    }

int n ;
    int[] up,down1,down2,p;
    List<Integer>[] list;
    public List<Integer> huangen(int n, int[][] edges) {
        this.n = n;
        this.up = new int[n];
        this.down1 = new int[n];
        this.down2 = new int[n];
        this.p = new int[n];
        list = new List[n];
        Arrays.setAll(list,e->new LinkedList<>());
        for(int[] edge:edges){
            int y = edge[0], x = edge[1];
            list[y].add(x);
            list[x].add(y);
        }
        dfs(-1,0);
        reroot(-1,0);
        return ans;
    }
    int dfs(int fa,int cur){
        for(int son:list[cur]){
            if(son==fa) continue;
            int f = dfs(cur,son) + ;//具体根据题目
            if(f >= down1[cur]){
                down2[cur] = down1[cur];
                down1[cur] = f;
                p[cur] = son;
            }else if( f > down2[cur]){
                down2[cur] = f;
            }
        }
        return down1[cur];
    }
    void reroot(int fa,int cur){
        for(int son:list[cur]){
            if(son==fa) continue;
            if(son==p[cur]){
                up[son] = Math.max(up[son],down2[cur] + );//具体根据题目
            }else{
                up[son] = Math.max(up[son],down1[cur] + );//具体根据题目
            }
            up[son] = Math.max(up[son],up[cur]+ );//具体根据题目
            reroot(cur,son);
        }
    }