Group all possible repeated characters with a regex I'm doing some code practice in hackerrank and I got the necessity to group all the possible combinations from a defined char or characters. i.e. we have the array index string e b c aa r y and I have the word caaab then I need to have 2 groups as the array is defining at index 3 the combination aa I should have the group1: caaab and group 2: caaab so the middle a is being part of both groups but I have been unable to do it, I'm using kotlin or Java so do really appreciate to get a hand from...