#yyds干货盘点# LeetCode程序员面试金典:单词频率

时间:2023-02-22 11:01:51

题目:

设计一个方法,找出任意指定单词在一本书中的出现频率。

你的实现应该支持如下操作:

WordsFrequency(book)构造函数,参数为字符串数组构成的一本书

get(word)查询指定单词在书中出现的频率

示例:

WordsFrequency wordsFrequency = new WordsFrequency({"i", "have", "an", "apple", "he", "have", "a", "pen"});

wordsFrequency.get("you"); //返回0,"you"没有出现过

wordsFrequency.get("have"); //返回2,"have"出现2次

wordsFrequency.get("an"); //返回1

wordsFrequency.get("apple"); //返回1

wordsFrequency.get("pen"); //返回1

代码实现:

class WordsFrequency {
private HashMap<String, Integer> map = new HashMap<>();

public WordsFrequency(String[] book) {
for (String word : book) {
map.put(word, map.getOrDefault(word, 0) + 1);
}
}

public int get(String word) {
return map.getOrDefault(word, 0);
}
}