This kata is part of the collection Mary’s Puzzle Books.
Mary brought home a “spot the differences” book. The book is full of a bunch of problems, and each problem consists of two strings that are similar. However, in each string there are a few characters that are different. An example puzzle from her book is:
String 1: “abcdefg”
String 2: “abcqetg”
Notice how the “d” from String 1 has become a “q” in String 2, and “f” from String 1 has become a “t” in String 2.
It’s your job to help Mary solve the puzzles. Write a program spot_diff/Spot that will compare the two strings and return a list with the positions where the two strings differ. In the example above, your program should return [3, 5] because String 1 is different from String 2 at positions 3 and 5.
• If both strings are the same, return 
• Both strings will always be the same length
• Capitalization and punctuation matter