Bubble sort algorithm description with implementation in C++,JAVA and PYTHON

1. Algorithms
Bubble Sort
Abdelrahman M. Saleh

2. List of contents
● Introduction
● Example w/ illustrating figures
● Algorithm
● implementation (Java, C++, Python)
● Performance Runtime
○ Best, Average and worst cases.
● Execution
● Other Notes

3. Introduction
● the simplest sorting algorithm that works by repeatedly swapping the adjacent
elements if they are in wrong order.
● Used in a polygon filling algorithm ,
○ bounding lines are sorted by their x coordinate at a specific (x-parallel) scan line
○ with incrementing y their order changes (two elements are swapped) only at
intersections of two lines

4. Example

5. Algorithm .
● Loop throw the array
● Loop throw the array-1
● If this index is bigger than it’s bigger adjacent
○ do swap values of index and it’s bigger adjacent .

6. Implementation .

7. C++ .
void bubbleSort(int a[], int len)
{
Bool swap = false ;
for(int i=0; i<len-1; i++)
{
for(int j=0; j<len-i-1; j++)
if(a[j] > a[j+1])
{
swap(&a[j], &a[j+1]) ;
swap = true ;
}
if(swap) break ;
}
}

8. JAVA .
void bubbleSort(int a[])
{
int len = arr.length; bool swap = false ;
for(int i=0; i<len-1; i++)
{
for(int j=0; j<len-i-1; j++)
if(a[j] > a[j+1])
{
int temp = arr[j];
arr[j] = arr[j+1];
arr[j+1] = temp;
}
if(swap) break ;
}
}

9. Python .
def bubbleSort(a):
for i in range(len(a)):
for j in range(0, len(a)-i-1):
if a[j] > a[j+1] :
a[j], a[j+1] = a[j+1], a[j]

10. Performance Runtime
● Time complexity Θ(n2) .
● Best case : when array is already sorted. Θ(n) .
● Worst case : when array is reverse sorted. Θ(n2)
● Average case : O(n) <f(n) < O(n2)

11. Execution .
Input array : [4, 6, 3, 2, 1, 9, 7]
First Action
Swap 6,3
Swap 6,2
Swap 6,1
Swap 7,9 => [4, 3, 2, 1, 6, 7, 9]
Second Action
Swap 4,3
Swap 4,2
Swap 4,1 => [3, 2, 1, 4, 6, 7, 9]
Third Action
Swap 3,2
Swap 3,1 => [2, 1, 3, 4, 6, 7, 9]
Fourth Action
Swap 2,1 => [1, 2, 3, 4, 6, 7, 9]
Output Array: [1, 2, 3, 4, 6, 7, 9]

12. Other Notes .
● Algorithmic Paradigm: Incremental Approach
● Sorting In Place: Yes
● Stable: Yes
● Online: Yes