题目描述

题目链接：804.唯一摩尔斯密码词

国际摩尔斯密码定义一种标准编码方式，将每个字母对应于一个由一系列点和短线组成的字符串， 比如:

• 'a'对应".-"
• 'b'对应"-..."
• 'c'对应"-.-."，以此类推。

为了方便，所有 26 个英文字母的摩尔斯密码表如下：
[".-","-...","-.-.","-..",".","..-.","--.","....","..",".---","-.-",".-..","--","-.","---",".--.","--.-",".-.","...","-","..-","...-",".--","-..-","-.--","--.."]

给你一个字符串数组 words ，每个单词可以写成每个字母对应摩尔斯密码的组合。

• 例如，"cab" 可以写成 "-.-..--..." ，(即 "-.-." + ".-" + "-..."字符串的结合)。我们将这样一个连接过程称作 单词翻译 。 对words中所有单词进行单词翻译，返回不同 单词翻译 的数量。

示例 1
输入: words = [“gin”, “zen”, “gig”, “msg”]
输出: 2
解释:
各单词翻译如下:
“gin” -> “–…-.”
“zen” -> “–…-.”
“gig” -> “–…–.”
“msg” -> “–…–.”
共有 2 种不同翻译, “–…-.” 和 “–…–.”.

示例 2
输入：words = [“a”]
输出：1

提示

• 1 <=words.length<= 100
• 1 <=words[i].length<= 12
• words[i]由小写英文字母组成

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解题核心

注意不同的字母对应不同的解码，但是组成的结果可能相同，所以需要去重

解法一：模拟

直接将每个单词翻译，然后用集合去重

public int uniqueMorseRepresentations(String[] words) {String[] password = new String[] {".-","-...","-.-.","-..",".","..-.","--.","....","..",".---","-.-",".-..","--","-.","---",".--.","--.-",".-.","...","-","..-","...-",".--","-..-","-.--","--.."};HashSet<String> set = new HashSet<>();for (String word : words) {StringBuilder temp = new StringBuilder();for (int j = 0; j < word.length(); j++) {int index = (word.charAt(j) - '0') - 49;temp.append(password[index]);}set.add(temp.toString());}return set.size();
}