Unique Morse Code Words Problem
Description
LeetCode Problem 804.
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:
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[".-","-...","-.-.","-..",".","..-.","--.","....","..",".---","-.-",".-..","--","-.","---",".--.","--.-",".-.","...","-","..-","...-",".--","-..-","-.--","--.."]
Given an array of strings words where 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 of “-.-.”, “.-“, and “-…”. We will call such a concatenation the transformation of a word.
Return the number of different transformations among all words we have.
Example 1:
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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 "--...--.".
Example 2:
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Input: words = ["a"]
Output: 1
Constraints:
- 1 <= words.length <= 100
- 1 <= words[i].length <= 12
- words[i] consists of lowercase English letters.
Sample C++ Code
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class Solution {
public:
int uniqueMorseRepresentations(vector<string>& words) {
vector<string> morse_code = { ".-", "-...", "-.-.", "-..", ".",
"..-.", "--.", "....", "..", ".---", "-.-", ".-..", "--",
"-.", "---", ".--.", "--.-", ".-.", "...", "-", "..-",
"...-", ".--", "-..-", "-.--", "--.." };
unordered_set<string> gen_codes;
for (auto word : words) {
string code = "";
for (auto ch : word)
code += morse_code[ch - 'a'];
gen_codes.insert(code);
}
return gen_codes.size();
}
};