Encrypt and Decrypt Strings — LeetCode 2227 Python Solution

The problem

You are given a character array keys containing unique characters and a string array values containing strings of length 2. You are also given another string array dictionary that contains all permitted original strings after decryption.

Example

Input

["Encrypter", "encrypt", "decrypt"]

Output

[null, "eizfeiam", 2]

Explanation

Encrypter encrypter = new Encrypter([['a', 'b', 'c', 'd'], ["ei", "zf", "ei", "am"], ["abcd", "acbd", "adbc", "badc", "dacb", "cadb", "cbda", "abad"]);

Python solution

class Encrypter:
    def __init__(self, keys: List[str], values: List[str], dictionary: List[str]):
        self.mp = dict(zip(keys, values))
        self.cnt = Counter(self.encrypt(v) for v in dictionary)

    def encrypt(self, word1: str) -> str:
        res = []
        for c in word1:
            if c not in self.mp:
                return ''
            res.append(self.mp[c])
        return ''.join(res)

    def decrypt(self, word2: str) -> int:
        return self.cnt[word2]


# Your Encrypter object will be instantiated and called as such:
# obj = Encrypter(keys, values, dictionary)
# param_1 = obj.encrypt(word1)
# param_2 = obj.decrypt(word2)

Complexity

Pattern: Trie

Store a set of words by their shared prefixes so lookups cost the length of the word. LeetCode 2227. Encrypt and Decrypt Strings is filed here because LeetCode tags it Trie, which is the vocabulary this hub collects.

The trie guide has the Python template for the pattern and the 49 LeetCode problems that use it.

Related problems