Buttercola: Leetcode: Group Shifted Strings

Buttercola: Leetcode: Group Shifted Strings

Leetcode: Group Shifted Strings

Given a string, we can "shift" each of its letter to its successive letter, for example: "abc" -> "bcd". We can keep "shifting" which forms the sequence:

"abc" -> "bcd" -> ... -> "xyz"

Given a list of strings which contains only lowercase alphabets, group all strings that belong to the same shifting sequence.

For example, given: ["abc", "bcd", "acef", "xyz", "az", "ba", "a", "z"], 
Return:

[    ["abc","bcd","xyz"],    ["az","ba"],    ["acef"],    ["a","z"]  ]

Note: For the return value, each inner list's elements must follow the lexicographic order.

Understand the problem:
The problem looks quite like the grouping anagrams. So the idea is the same: for each string, find out its "original" format, and check if the hash map contains this original string. If yes, put into the map. 

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