Hackerrank - Sorting: Bubble Sort Solution

Consider the following version of Bubble Sort:

for (int i = 0; i < n; i++) {
    
    for (int j = 0; j < n - 1; j++) {
        // Swap adjacent elements if they are in decreasing order
        if (a[j] > a[j + 1]) {
            swap(a[j], a[j + 1]);
        }
    }
    
}

Given an array of integers, sort the array in ascending order using the Bubble Sort algorithm above. Once sorted, print the following three lines:

1. Array is sorted in numSwaps swaps., where  is the number of swaps that took place.
2. First Element: firstElement, where  is the first element in the sorted array.
3. Last Element: lastElement, where  is the last element in the sorted array.

Hint: To complete this challenge, you must add a variable that keeps a running tally of all swaps that occur during execution.

For example, given a worst-case but small array to sort:  we go through the following steps:

swap    a       
0       [6,4,1]
1       [4,6,1]
2       [4,1,6]
3       [1,4,6]

It took  swaps to sort the array. Output would beArray is sorted in 3 swaps. First Element: 1 Last Element: 6

Function Description

Complete the function countSwaps in the editor below. It should print the three lines required, then return.

countSwaps has the following parameter(s):

• a: an array of integers .

Input Format

The first line contains an integer, , the size of the array .
The second line contains  space-separated integers .

Constraints

Output Format

You must print the following three lines of output:

1. Array is sorted in numSwaps swaps., where  is the number of swaps that took place.
2. First Element: firstElement, where  is the first element in the sorted array.
3. Last Element: lastElement, where  is the last element in the sorted array.

Sample Input 0

3
1 2 3

Sample Output 0

Array is sorted in 0 swaps.
First Element: 1
Last Element: 3

Explanation 0
The array is already sorted, so  swaps take place and we print the necessary three lines of output shown above.

Sample Input 1

3
3 2 1

Sample Output 1

Array is sorted in 3 swaps.
First Element: 1
Last Element: 3

Explanation 1
The array is not sorted, and its initial values are: . The following  swaps take place:

At this point the array is sorted and we print the necessary three lines of output shown above.

Solution in Python

from itertools import product
def countSwaps(a):
    swaps = 0
    for i,j in product(range(len(a)),range(len(a)-1)):
        if a[j]>a[j+1]:
            a[j],a[j+1] = a[j+1],a[j]
            swaps += 1
    print("Array is sorted in %s swaps." %swaps)
    print("First Element:", a[0])
    print("Last Element:", a[-1])

n = int(input())
a = list(map(int,input().split()))
countSwaps(a)

Additional Info

The following two gives same output

for i in range(n):
    for j in range(n-1):
    	print(i,j)

from itertools import product
for i,j in product(range(n),range(n-1)):
    print(i,j)