804. Unique Morse Code Words

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804. Unique Morse Code Words

题目描述

International Morse Code defines a standard encoding where each letter is mapped to a series of dots and dashes, as follows: “a” maps to “.-“, “b” maps to “-…”, “c” maps to “-.-.”, and so on.

For convenience, the full table for the 26 letters of the English alphabet is given below:

[“.-“,”-…”,”-.-.”,”-..”,”.”,”..-.”,”–.”,”….”,”..”,”.—“,”-.-“,”.-..”,”–”,”-.”,”—“,”.–.”,”–.-“,”.-.”,”…”,”-“,”..-“,”…-“,”.–”,”-..-“,”-.–”,”–..”]
Now, given a list of words, each word can be written as a concatenation of the Morse code of each letter. For example, “cab” can be written as “-.-.-….-“, (which is the concatenation “-.-.” + “-…” + “.-“). We’ll call such a concatenation, the transformation of a word.

Return the number of different transformations among all words we have.

Example:

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Input: words = ["gin", "zen", "gig", "msg"]
Output: 2
Explanation: 
The transformation of each word is:
"gin" -> "--...-."
"zen" -> "--...-."
"gig" -> "--...--."
"msg" -> "--...--."
There are 2 different transformations, "--...-." and "--...--.".

Note:

  • The length of words will be at most 100.
  • Each words[i] will have length in range [1, 12].
  • words[i] will only consist of lowercase letters.

题目大意

根据摩斯电码，生成对应的摩斯密码，返回不同摩斯密码的个数。

解题思路

Set

代码

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class Solution {
    func uniqueMorseRepresentations(_ words: [String]) -> Int {
        var morseCode = [".-","-...","-.-.","-..",".","..-.","--.","....","..",".---",
                         "-.-",".-..","--","-.","---",".--.","--.-",".-.","...",
                         "-","..-","...-",".--","-..-","-.--","--.."]
        var unique = Set<String>()
        for word in words {
            var str = ""
            for char in word.unicodeScalars {
                str.append(morseCode[Int(char.value - 97)])
            }
            unique.insert(str)
        }
        return unique.count
    }
}
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