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.
class Solution:
def letterCasePermutation(self, S: str) -> List[str]:
ans = []
self.dfs(S, 0, ans, [])
return ans
def dfs(self, S, i, ans, path):
if i == len(S):
ans.append(''.join(path))
return
self.dfs(S, i+1, ans, path + [S[i]])
if S[i].isalpha():
self.dfs(S, i+1, ans, path + [S[i].swapcase()])