[LeetCode] 17. Letter Combinations of a Phone Number

轉自LeetCode

Given a digit string, return all possible letter combinations that the number could represent.

A mapping of digit to letters (just like on the telephone buttons) is given below.

Input:Digit string "23"
Output: ["ad", "ae", "af", "bd", "be", "bf", "cd", "ce", "cf"].

<Solution>

這題簡單來說，就是根據 input 的長度去排列組合

例如 input 是 "234"，那 output 會是 "adg"、"adh"、"adi"、"aeg"等

從這邊可以看出，可以用DFS來做這件事

code 如下


kotlin