# Bubble Sort in Ruby

## Overview

Bubble Sort is an extremely simple and generally poor-performing algorithm for sorting which iterates through a list and swaps values that are in the wrong order. This process is repeated until the list is fully sorted. It has a worst-case and average complexity of `O(n^2)`

.

## Concise

```
def bubble_sort(a)
s = false
(a.length-1).times do |i|
if a[i] > a[i+1]
a[i], a[i+1] = a[i+1], a[i]
s = true
end
end
p a
if s
bubble_sort(a)
else
return a
end
end
a = (0..9).to_a.sort{ rand() - 0.5 }[0..9]
p a
s = bubble_sort(a)
puts s.inspect
```

## Verbose

```
# Bubble Sort in Ruby
#
# Input: A sequence of numbers in any order.
# Output: An ordered sequence from smallest number to largest.
#
def bubble_sort(numbers)
# Set an initial value of false for swapped, because nothing has been swapped.
swapped = false
# Iterate through the array, swapping each value if it is larger than
# the next value in the array. If the values are swapped, set our swapped
# variable to true so that we know another pass is needed.
(numbers.length-1).times do |i|
if numbers[i] > numbers[i+1]
numbers[i], numbers[i+1] = numbers[i+1], numbers[i]
swapped = true
end
end
p numbers
if swapped
bubble_sort(numbers)
else
return numbers
end
end
# Generate array of ten random integers.
unsorted = (0..9).to_a.sort{ rand() - 0.5 }[0..9]
puts unsorted.inspect
# Sort.
sorted = bubble_sort(unsorted)
puts sorted.inspect
```

## Sample Input and Output

```
$ ruby bubble_sort.rb
[3, 2, 7, 6, 5, 9, 4, 1, 8, 0]
[2, 3, 6, 5, 7, 4, 1, 8, 0, 9]
[2, 3, 5, 6, 4, 1, 7, 0, 8, 9]
[2, 3, 5, 4, 1, 6, 0, 7, 8, 9]
[2, 3, 4, 1, 5, 0, 6, 7, 8, 9]
[2, 3, 1, 4, 0, 5, 6, 7, 8, 9]
[2, 1, 3, 0, 4, 5, 6, 7, 8, 9]
[1, 2, 0, 3, 4, 5, 6, 7, 8, 9]
[1, 0, 2, 3, 4, 5, 6, 7, 8, 9]
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
```