Count Dictionary Originals Sharing an Encryption

### Problem Implement an `Encrypter` object from distinct lowercase `keys`, their corresponding two-character `values`, and a dictionary of permitted original words. Different keys may share the same pair. `encrypt(word1)` replaces each character by its mapped pair and concatenates the pairs, returning an empty string if a character has no mapping. `decrypt(word2)` considers its consecutive two-character blocks: each block may be replaced by any key mapped to that pair. Return the number of distinct resulting words that occur in the dictionary. Preserve the constructor and both methods. ```cpp class Encrypter { public: Encrypter(vector<char>& keys, vector<string>& values, vector<string>& dictionary); string encrypt(string word1); int decrypt(string word2); }; ``` ### Examples **Example 1:** ```text keys = ['a','b'], values = ["xy","xy"], dictionary = ["a","b","ab"] Calls: encrypt("ab"), decrypt("xy"), decrypt("xyxy") Results: "xyxy", 2, 1 Explanation: Both single-letter dictionary words share the first ciphertext. ``` **Example 2:** ```text keys = ['a'], values = ["zz"], dictionary = ["a","c"] Calls: encrypt("a"), decrypt("zz"), decrypt("yy") Results: "zz", 1, 0 Explanation: The unmapped dictionary word c contributes to no valid ciphertext. ``` ### Constraints - `1 <= keys.length == values.length <= 26`; keys are unique and every value has length two. - `1 <= dictionary.length <= 100`; dictionary entries are distinct and lengths lie in `[1,100]`. - `1 <= word1.length <= 2000`; word1 characters are guaranteed mapped. - word2 has even length in `[2,200]`; all strings use lowercase letters. - At most 200 total encrypt/decrypt calls. ### Clarifying Questions Different keys may share a mapped pair, so a ciphertext can have several permitted dictionary originals. Dictionary words may contain unmapped letters; only word1 is guaranteed mapped. ```hint Inspect the structure Can decryption be answered by indexing encrypted dictionary words rather than expanding every inverse mapping? ``` ### Reasoning checkpoints - Implement the specified forward mapping and count all permitted dictionary originals for a ciphertext. - Handle several keys sharing one pair without losing distinct dictionary possibilities. - Exclude words that cannot be formed from the mapping and preserve the full constructor/method protocol. ### Optional extensions How would you support adding and removing permitted dictionary words?