Bubble sort

• A very basic way to sort numbers in ascending or descending order
• How it works ?
  • Now imagine an unsorted array of N items. Now we want to sort it ascending order. We will start with comparing first 2 elements, if first element is larger than second, we will swap this 2 elements or else we will go on comapring second and third element, here we will do same thing till second last and last element. So that was one iteration, we may have to go N iterations of this.

Pseudocode

      procedure bubbleSort(A : list of sortable items )
          n = length(A)
          repeat
              swapped = false
              for i = 1 to n-1 inclusive do
                  /* if this pair is out of order */
                  if A[i-1] > A[i] then
                      /* swap them and remember something changed */
                      swap( A[i-1], A[i] )
                      swapped = true
                  end if
              end for
          until not swapped
      end procedure
      

Use this interactive animation to understand it better...

Go ahead, enter a list of numbers separated by commas (eg : 9,8,7,6,5,4,3,2,1 ) and click sort..

( Note : Sorting here in ascending order )

Bubble sort is very simple search algorithm, but surely not very time efficient for large lists, as it's worst time complexity is O( N² ).