特里的复杂性和搜索 [英] Trie complexity and searching

问题描述

什么是创建单词的列表的一个线索的复杂性，什么是复杂搜索另一组单词在线索？ 我应该使用线索字符串搜索，当我有哈希表？

解决方案

在创建线索的复杂性是 O（宽*长），其中是W 是字的数目，和→是词的平均长度：您需要执行→查找平均每个 W的词语的设定。

也是一样的找单词后：执行→步骤为每个是W 字

哈希插入和查找具有相同的复杂性：每个字，你需要检查的平等，这需要 0（1），为的总体复杂性 O（宽*长）。

如果你需要查找整个单词，哈希表比较简单。但是，你不能看由他们使用哈希表preFIX字;如果preFIX为基础的查找是不感兴趣的您，请使用哈希表;否则，使用一个线索。

What is the complexity of creating a trie of a list of words and what is complexity of searching other set of word in that trie? Should I use trie for string searching, when i have hashtable?

解决方案

The complexity of creating a trie is O(W*L), where W is the number of words, and L is an average length of the word: you need to perform L lookups on the average for each of the W words in the set.

Same goes for looking up words later: you perform L steps for each of the W words.

Hash insertions and lookups have the same complexity: for each word you need to check equality, which takes O(L), for the overall complexity of O(W*L).

If you need to look up entire words, hash table is easier. However, you cannot look up words by their prefix using a hash table; If prefix-based lookups are of no interest to you, use a hash table; otherwise, use a trie.

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