[Swift]LeetCode1032. 字符流 | Stream of Characters

Implement the StreamChecker class as follows:

  • StreamChecker(words): Constructor, init the data structure with the given words.
  • query(letter): returns true if and only if for some k >= 1, the last k characters queried (in order from oldest to newest, including this letter just queried) spell one of the words in the given list.

Example:

StreamChecker streamChecker = new StreamChecker(["cd","f","kl"]); // init the dictionary.
streamChecker.query('a');          // return false
streamChecker.query('b');          // return false
streamChecker.query('c');          // return false
streamChecker.query('d');          // return true, because 'cd' is in the wordlist
streamChecker.query('e');          // return false
streamChecker.query('f');          // return true, because 'f' is in the wordlist
streamChecker.query('g');          // return false
streamChecker.query('h');          // return false
streamChecker.query('i');          // return false
streamChecker.query('j');          // return false
streamChecker.query('k');          // return false
streamChecker.query('l');          // return true, because 'kl' is in the wordlist

Note:

  • 1 <= words.length <= 2000
  • 1 <= words[i].length <= 2000
  • Words will only consist of lowercase English letters.
  • Queries will only consist of lowercase English letters.
  • The number of queries is at most 40000.

按下述要求实现 StreamChecker 类:

  • StreamChecker(words):构造函数,用给定的字词初始化数据结构。
  • query(letter):如果存在某些 k >= 1,可以用查询的最后 k个字符(按从旧到新顺序,包括刚刚查询的字母)拼写出给定字词表中的某一字词时,返回 true。否则,返回 false

示例:

StreamChecker streamChecker = new StreamChecker(["cd","f","kl"]); // 初始化字典
streamChecker.query('a');          // 返回 false
streamChecker.query('b');          // 返回 false
streamChecker.query('c');          // 返回 false
streamChecker.query('d');          // 返回 true,因为 'cd' 在字词表中
streamChecker.query('e');          // 返回 false
streamChecker.query('f');          // 返回 true,因为 'f' 在字词表中
streamChecker.query('g');          // 返回 false
streamChecker.query('h');          // 返回 false
streamChecker.query('i');          // 返回 false
streamChecker.query('j');          // 返回 false
streamChecker.query('k');          // 返回 false
streamChecker.query('l');          // 返回 true,因为 'kl' 在字词表中。

提示:

  • 1 <= words.length <= 2000
  • 1 <= words[i].length <= 2000
  • 字词只包含小写英文字母。
  • 待查项只包含小写英文字母。
  • 待查项最多 40000 个。

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转载自www.cnblogs.com/strengthen/p/10744673.html