# Question

Formatted question description: https://leetcode.ca/all/249.html

```
249 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.
```

# Algorithm

The relative distance between each letter of the string and the first character is equal.

For example, abc and efg are mutually offset. For abc, the distance between b and a is 1, and the distance between c and a is 2. For efg, the distance between f and e is 1, and the distance between g and e is 2. .

Let’s look at another example. The distance between az and yx, z and a is 25, and the distance between x and y is also 25 (direct subtraction is -1, which is the reason for adding 26 and taking the remainder).

Then, in this case, all strings that are offset from each other have a unique distance difference. According to this, the mapping can be well grouped.

# Code

Java