Bubble sort Explained

Bubble sort complexity:

O(n^2)

Pseudocode:

src: https://www.youtube.com/watch?v=xli_FI7CuzA

Bubble sort PHP code example:

function bubble_sort($arr) {
    $size = count($arr)-1;
    for ($i=0; $i<$size; $i++) {
        for ($j=0; $j<$size-$i; $j++) {
            $k = $j+1;
            if ($arr[$k] < $arr[$j]) {
                // Swap elements at indices: $j, $k
                list($arr[$j], $arr[$k]) = array($arr[$k], $arr[$j]);
            }
        }
    }
    return $arr;
}

src: https://stackoverflow.com/questions/9001294/bubble-sort-implementation-in-php

Bubble sort Python code example:

# Python program for implementation of Bubble Sort

def bubbleSort(arr):
	n = len(arr)
	# optimize code, so if the array is already sorted, it doesn't need
	# to go through the entire process
	swapped = False
	# Traverse through all array elements
	for i in range(n-1):
		# range(n) also work but outer loop will
		# repeat one time more than needed.
		# Last i elements are already in place
		for j in range(0, n-i-1):

			# traverse the array from 0 to n-i-1
			# Swap if the element found is greater
			# than the next element
			if arr[j] > arr[j + 1]:
				swapped = True
				arr[j], arr[j + 1] = arr[j + 1], arr[j]
		
		if not swapped:
			# if we haven't needed to make a single swap, we 
			# can just exit the main loop.
			return


# Driver code to test above
arr = [64, 34, 25, 12, 22, 11, 90]

bubbleSort(arr)

print("Sorted array is:")
for i in range(len(arr)):
	print("% d" % arr[i], end=" ")

src: https://www.geeksforgeeks.org/python-program-for-bubble-sort/

Merge sort as better alternative?

Bubble sort Vs Merge sort
O(n^2) Vs O(n*log(n))

https://www.youtube.com/watch?v=4VqmGXwpLqc