text: 1. DS - Linked List
          - Swap nodes in a linked list without swapping data
  
  2. DS - array
          - Maximum sum such that no two elements are adjacent
            (https://www.geeksforgeeks.org/maximum-sum-such-that-no-two-elements-are-adjacent)
          - Given an array arr[], find the maximum j – i such that arr[j] > arr[i]
            (https://www.geeksforgeeks.org/given-an-array-arr-find-the-maximum-j-i-such-that-arrj-arri/)
          - Find the smallest positive number missing from an unsorted array
            (https://www.geeksforgeeks.org/find-the-smallest-positive-number-missing-from-an-unsorted-array/)
          - Given an array of of size n and a number k, find all elements that appear more than n/k times
            (https://www.geeksforgeeks.org/given-an-array-of-of-size-n-finds-all-the-elements-that-appear-more-than-nk-times/)
  
  3. Seach and Sorting
  	- http://www.geeksforgeeks.org/sort-n-numbers-range-0-n2-1-linear-time/
  