804. 唯一摩尔斯密码词

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题目

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 "-.-.", 等等。

为了方便，所有26个英文字母对应摩尔斯密码表如下：

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[".-","-...","-.-.","-..",".","..-.","--.","....","..",".---","-.-",".-..","--","-.","---",".--.","--.-",".-.","...","-","..-","...-",".--","-..-","-.--","--.."]

给定一个单词列表，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。
返回我们可以获得所有词不同单词翻译的数量。

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例如:
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 "--...--.".

提示：

  • 单词列表words 的长度不会超过 100。
  • 每个单词 words[i]的长度范围为 [1, 12]。
  • 每个单词 words[i]只包含小写字母。

解法

解法一：

转换，去重

Java

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class Solution {
    private void init(Map<Character, String> map) {
		String[] mos = new String[] {".-","-...","-.-.","-..",".","..-.","--.","....","..",".---","-.-",".-..","--","-.","---",".--.","--.-",".-.","...","-","..-","...-",".--","-..-","-.--","--.."};
		int i = 0;
		for (char c = 'a'; c <= 'z';c++) {
			map.put(c, mos[i++]);
		}
	}
	
	private String getWordMos(Map<Character, String> map, String word) {
		StringBuilder sb = new StringBuilder();
		for (int i = 0;i < word.length();i++) {
			sb.append(map.get(word.charAt(i)));
		}
		return sb.toString();
	}
	
	public int uniqueMorseRepresentations(String[] words) {
		Map<Character, String> map = new HashMap<>();
		init(map);
		HashSet<String> set = new HashSet<>();
		for(String s : words) {
			set.add(getWordMos(map, s));
		}
        return set.size();
    }
}
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