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Md Ariful Haque @mah-shamim

Letter Tile Possibilities Calculator

1079. Letter Tile Possibilities: Use backtracking DFS to generate all possible permutations of tiles for lengths 1 to n. Manage counts with frequency map to avoid duplicates. Complexity manageable due to input length constraint.

1079. Letter Tile Possibilities
Difficulty: Medium
Topics: Hash Table, String, Backtracking, Counting
You have n  tiles, where each tile has one letter tiles[i] printed on it.
Return the number of possible non-empty sequences of letters you can make using the letters printed on those tiles.
Example 1:

Input: tiles = "AAB"
Output: 8
Explanation: The possible sequences are "A", "B", "AA", "AB", "BA", "AAB", "ABA", "BAA".

Example 2:

Input: tiles = "AAABBC"
Output: 188

Example 3:

Input: tiles = "V"
Output: 1

Constraints:

1 <= tiles.length <= 7
tiles consists of uppercase English letters.

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