notes/OJ notes/pages/Leetcode Letter-Case-Combination.md

Leetcode Letter-Case-Combination

2022-07-20 14:19

Algorithms:

#algorithm #backtrack

Difficulty:

#coding_problem #difficulty_medium

Additional tags:

#leetcode

Revisions:

N/A

Related topics:

Links:

• Link to problem

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Problem

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

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

Examples

Example 1:

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

Example 2:

**Input:** s = "3z4"
**Output:** ["3z4","3Z4"]

Constraints

Constraints:

• 1 <= s.length <= 12
• s consists of lowercase English letters, uppercase English letters, and digits.

Thoughts

[!summary] This is a #backtrack problem.

Solution