leetcode 804. Unique Morse Code Words(python)

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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:

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.

解析

根据题意,已经有了 26 个字母对应的摩斯码,那么只需要用字典类型的对象,在遍历每个 word 的时候,将 word 中的每个字符转换为摩斯码并连成字符串,最后将得到的所有字符串去重即可得到结果个数。

解答

class Solution(object):
    def uniqueMorseRepresentations(self, words):
        """
        :type words: List[str]
        :rtype: int
        """
        res = set()
        morse = [".-","-...","-.-.","-..",".","..-.","--.","....","..",".---","-.-",".-..","--","-.","---",".--.","--.-",".-.","...","-","..-","...-",".--","-..-","-.--","--.."]
        for word in words:
            tmp = ""
            for c in word:
                tmp += morse[ord(c)-97]
            res.add(tmp)
        return len(res)
        	      
		

运行结果

Runtime: 20 ms, faster than 81.22% of Python online submissions for Unique Morse Code Words.
Memory Usage: 13.6 MB, less than 47.68% of Python online submissions for Unique Morse Code Words.

原题链接:leetcode.com/problems/un…

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