Easy
You are given the strings key and message, which represent a cipher key and a secret message, respectively. The steps to decode message are as follows:
- Use the first appearance of all 26 lowercase English letters in
keyas the order of the substitution table. - Align the substitution table with the regular English alphabet.
- Each letter in
messageis then substituted using the table. - Spaces
' 'are transformed to themselves.
- For example, given
key = "happy boy"(actual key would have at least one instance of each letter in the alphabet), we have the partial substitution table of ('h' -> 'a','a' -> 'b','p' -> 'c','y' -> 'd','b' -> 'e','o' -> 'f').
Return the decoded message.
Example 1:
Input: key = "the quick brown fox jumps over the lazy dog", message = "vkbs bs t suepuv" Output: "this is a secret" Explanation: The diagram above shows the substitution table. It is obtained by taking the first appearance of each letter in "the quick brown fox jumps over the lazy dog".
Example 2:
Input: key = "eljuxhpwnyrdgtqkviszcfmabo", message = "zwx hnfx lqantp mnoeius ycgk vcnjrdb" Output: "the five boxing wizards jump quickly" Explanation: The diagram above shows the substitution table. It is obtained by taking the first appearance of each letter in "eljuxhpwnyrdgtqkviszcfmabo".
Constraints:
26 <= key.length <= 2000keyconsists of lowercase English letters and' '.keycontains every letter in the English alphabet ('a'to'z') at least once.1 <= message.length <= 2000messageconsists of lowercase English letters and' '.
class Solution:
def decodeMessage(self, key: str, message: str) -> str:
d = {}
d[" "] = " "
count = 0
for i, k in enumerate(key):
if k not in d:
d[k] = chr(ord('a')+count)
count+=1
msg = []
for m in message:
msg.append(d[m])
return "".join(msg)