在trie树中使用的双数组

Question

我尝试通过this link中的双数组树来理解trie树实现。

1. 在碰撞时，它应该重新定位。从伪代码，为什么它还应该更新check[base[base[s] + c] + d]和base[b+c]？

任何人都可以用简单的语言解释它吗？

Procedure Relocate(s : state; b : base_index)
{ Move base for state s to a new place beginning at b }
begin
    foreach input character c for the state s
    { i.e. foreach c such that check[base[s] + c]] = s }
    begin
        check[b + c] := s;     { mark owner }
        base[b + c] := base[base[s] + c];     { copy data }
        { the node base[s] + c is to be moved to b + c;
          Hence, for any i for which check[i] = base[s] + c, update check[i] to b + c }
        foreach input character d for the node base[s] + c
        begin
            check[base[base[s] + c] + d] := b + c
        end;
        check[base[s] + c] := none     { free the cell }
    end;
    base[s] := b
end