[leetCode] 784. Letter Case Permutation (Python)

Given a string S, we can transform every letter individually to be lowercase or uppercase to create another string.

Return a list of all possible strings we could create. You can return the output in any order.

 

Example 1:

Input: S = "a1b2"
Output: ["a1b2","a1B2","A1b2","A1B2"]

Example 2:

Input: S = "3z4"
Output: ["3z4","3Z4"]

Example 3:

Input: S = "12345"
Output: ["12345"]

Example 4:

Input: S = "0"
Output: ["0"]

 

Constraints:

• S will be a string with length between 1 and 12.
• S will consist only of letters or digits.

Solution

class Solution:
    def letterCasePermutation(self, S: str) -> List[str]:
        answer = [""]
        
        for i in range(len(S)):
            temp = []
            for j in range(len(answer)):
                if S[i].isalpha():
                    temp.append(answer[j] + S[i].lower())
                    temp.append(answer[j] + S[i].upper())
                else:
                    temp.append(answer[j] + S[i])
                    
            answer = temp
            
        return answer

SOMJANG/CODINGTEST_PRACTICE