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)查询指定单词在数中出现的频率
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
提示:
book[i]
中只包含小写字母1 <= book.length <= 100000
1 <= book[i].length <= 10
get
函数的调用次数不会超过100000
来源:力扣(LeetCode)
链接:https://leetcode-cn.com/problems/words-frequency-lcci
我的答案
import java.util.HashMap;
import java.util.Map;
class WordsFrequency {
private Map<String,Integer> map;
public WordsFrequency(String[] book) {
map = new HashMap<String, Integer>();
int num = 1;
for(int i=0;i<book.length;i++){
if(map.containsKey(book[i])){
num = map.get(book[i])+1;
}
map.put(book[i],num);
num=1;
}
}
public int get(String word) {
if(map.containsKey(word)){
return map.get(word);
}else{
return 0;
}
}
}
情况
真不觉得这个题目还是中等难度的。