SDE - 1

You are given an integer array 'ARR' of size 'N' and an integer 'S'. Your task is to return the list of all pairs of elements such that each sum of elements of each pair equals 'S'.

Note:

Each pair should be sorted i.e the first value should be less than or equals to the second value. 

Return the list of pairs sorted in non-decreasing order of their first value. In case if two pairs have the same first value, the pair with a smaller second value should come first.

You have been given a linked list where each node has a single character. You have also been given a string 'STR'.

You have to remove all the occurrences of string STR from the linked list.

Note:

1. Start checking from the end of the linked list and not from the beginning. For example, if the linked list is ( a, b, a ,b, a)  and the string is equal to “aba” , then the answer should be (a b), not (b a).

2. After removing an occurrence check again for new formations.