diff --git a/BubbleSort.py b/BubbleSort.py index 0740c066b..d74b5b223 100644 --- a/BubbleSort.py +++ b/BubbleSort.py @@ -1,32 +1,32 @@ def simple_bubble_sort(int_list): - count = len(int_list) - swapped = True - while (swapped): - swapped = False - for j in range(count - 1): - if (int_list[j] > int_list[j + 1]): - int_list[j], int_list[j + 1] = int_list[j + 1], int_list[j] - swapped = True - return int_list + count = len(int_list) + swapped = True + while (swapped): + swapped = False + for j in range(count - 1): + if (int_list[j] > int_list[j + 1]): + int_list[j], int_list[j + 1] = int_list[j + 1], int_list[j] + swapped = True + return int_list def main(): - try: - print("Enter numbers separated by spaces:") - s = raw_input() - inputs = list(map(int, s.split(' '))) - if len(inputs) < 2: - print('No Enough values to sort!') - raise Exception + try: + print("Enter numbers separated by spaces:") + s = raw_input() + inputs = list(map(int, s.split(' '))) + if len(inputs) < 2: + print('No Enough values to sort!') + raise Exception - except Exception as e: - print(e) - else: - sorted_input = simple_bubble_sort(inputs) - print('\nSorted list (min to max): {}'.format(sorted_input)) + except Exception as e: + print(e) + else: + sorted_input = simple_bubble_sort(inputs) + print('\nSorted list (min to max): {}'.format(sorted_input)) if __name__ == '__main__': - print('==== Bubble Sort ====\n') - main() + print('==== Bubble Sort ====\n') + main() diff --git a/InsertionSort.py b/InsertionSort.py index 5602b2967..74cbc57e8 100644 --- a/InsertionSort.py +++ b/InsertionSort.py @@ -1,32 +1,32 @@ def simple_insertion_sort(int_list): - count = len(int_list) - for i in range(1, count): - temp = int_list[i] - j = i - 1 - while(j >= 0 and temp < int_list[j]): - int_list[j + 1] = int_list[j] - j -= 1 - int_list[j + 1] = temp + count = len(int_list) + for i in range(1, count): + temp = int_list[i] + j = i - 1 + while(j >= 0 and temp < int_list[j]): + int_list[j + 1] = int_list[j] + j -= 1 + int_list[j + 1] = temp - return int_list + return int_list def main(): - try: - print("Enter numbers separated by spaces:") - s = raw_input() - inputs = list(map(int, s.split(' '))) - if len(inputs) < 2: - print('No Enough values to sort!') - raise Exception + try: + print("Enter numbers separated by spaces:") + s = raw_input() + inputs = list(map(int, s.split(' '))) + if len(inputs) < 2: + print('No Enough values to sort!') + raise Exception - except Exception as e: - print(e) - else: - sorted_input = simple_insertion_sort(inputs) - print('\nSorted list (min to max): {}'.format(sorted_input)) + except Exception as e: + print(e) + else: + sorted_input = simple_insertion_sort(inputs) + print('\nSorted list (min to max): {}'.format(sorted_input)) if __name__ == '__main__': - print('==== Insertion Sort ====\n') - main() + print('==== Insertion Sort ====\n') + main() diff --git a/LinearSearch.py b/LinearSearch.py index cdff26b78..61c9e0dd5 100644 --- a/LinearSearch.py +++ b/LinearSearch.py @@ -1,24 +1,24 @@ def sequential_search(alist, target): - for index, item in enumerate(alist): - if item == target: - print("Found target {} at index {}".format(target, index)) - break - else: - print("Not found") + for index, item in enumerate(alist): + if item == target: + print("Found target {} at index {}".format(target, index)) + break + else: + print("Not found") def main(): - try: - print("Enter numbers separated by spaces") - s = raw_input() - inputs = list(map(int, s.split(' '))) - target = int(raw_input('\nEnter a single number to be found in the list: ')) - except Exception as e: - print(e) - else: - sequential_search(inputs, target) + try: + print("Enter numbers separated by spaces") + s = raw_input() + inputs = list(map(int, s.split(' '))) + target = int(raw_input('\nEnter a single number to be found in the list: ')) + except Exception as e: + print(e) + else: + sequential_search(inputs, target) if __name__ == '__main__': - print('==== Insertion Sort ====\n') - main() + print('==== Linear Search ====\n') + main() diff --git a/QuickSort.py b/QuickSort.py index 89db5a6a3..7221cfe75 100644 --- a/QuickSort.py +++ b/QuickSort.py @@ -1,31 +1,33 @@ -def quicksort(A, p, r): +def quick_sort(A, p, r): if p < r: q = partition(A, p, r) - quicksort(A, p, q - 1) - quicksort(A, q + 1, r) + quick_sort(A, p, q - 1) + quick_sort(A, q + 1, r) + return A def partition(A, p, r): - x = A[r] i = p - 1 for j in range(p, r): - if A[j] <= x: + if A[j] <= A[r]: i += 1 - tmp = A[i] - A[i] = A[j] - A[j] = tmp - tmp = A[i+1] - A[i+1] = A[r] - A[r] = tmp + A[i], A[j] = A[j], A[i] + A[i + 1], A[r] = A[r], A[i + 1] return i + 1 -if __name__ == "__main__": - print('Enter values seperated by space:') - A = [int (item) for item in input().split(' ')] - # A = [23, 45, 43, 12, 67, 98, 123, 99] - # partition(A, 0, 7) - print(A) - quicksort(A, 0, 7) - print(A) +def main(): + try: + print("Enter numbers separated by spaces") + s = raw_input() + inputs = list(map(int, s.split(' '))) + except Exception as e: + print(e) + else: + sorted_input = quick_sort(inputs, 0, len(inputs) - 1) + print('\nSorted list (min to max): {}'.format(sorted_input)) + +if __name__ == '__main__': + print('==== Quick Sort ====\n') + main() diff --git a/README.md b/README.md index d88c5c675..b44e12e93 100644 --- a/README.md +++ b/README.md @@ -1,14 +1,13 @@ # The Algoritms - Python -### **All Algorithms implemented in Python!** +### All Algorithms implemented in Python! These are for demonstration purposes only. There are many implementations of sorts in the Python standard library that are much better for performance reasons. -## Sorting - +## Sorting Algorithms ### Binary - +Add comments here ### Bubble ![alt text][bubble-image] @@ -16,7 +15,6 @@ These are for demonstration purposes only. There are many implementations of sor From [Wikipedia][bubble-wiki]: Bubble sort, sometimes referred to as sinking sort, is a simple sorting algorithm that repeatedly steps through the list to be sorted, compares each pair of adjacent items and swaps them if they are in the wrong order. The pass through the list is repeated until no swaps are needed, which indicates that the list is sorted. __Properties__ -* Stable * Worst case performance O(n^2) * Best case performance O(n) * Average case performance O(n^2) @@ -26,7 +24,7 @@ __Properties__ ### Caesar - +Add comments here ### Insertion ![alt text][insertion-image] @@ -34,7 +32,6 @@ __Properties__ From [Wikipedia][insertion-wiki]: Insertion sort is a simple sorting algorithm that builds the final sorted array (or list) one item at a time. It is much less efficient on large lists than more advanced algorithms such as quicksort, heapsort, or merge sort. __Properties__ -* Stable * Worst case performance O(n^2) * Best case performance O(n) * Average case performance O(n^2) @@ -43,6 +40,18 @@ __Properties__ ###### View the algorithm in [action][insertion-toptal] +## Quick +![alt text][quick-image] + +From [Wikipedia][quick-wiki]: Quicksort (sometimes called partition-exchange sort) is an efficient sorting algorithm, serving as a systematic method for placing the elements of an array in order. + +__Properties__ +* Worst case performance O(n^2) +* Best case performance O(n log n) or O(n) with three-way partition +* Average case performance O(n^2) + + +###### View the algorithm in [action][quick-toptal] [bubble-toptal]: https://www.toptal.com/developers/sorting-algorithms/bubble-sort [bubble-wiki]: https://en.wikipedia.org/wiki/Bubble_sort @@ -51,3 +60,7 @@ __Properties__ [insertion-toptal]: https://www.toptal.com/developers/sorting-algorithms/insertion-sort [insertion-wiki]: https://en.wikipedia.org/wiki/Insertion_sort [insertion-image]: https://upload.wikimedia.org/wikipedia/commons/7/7e/Insertionsort-edited.png "Insertion Sort" + +[quick-toptal]: https://www.toptal.com/developers/sorting-algorithms/quick-sort +[quick-wiki]: https://en.wikipedia.org/wiki/Quicksort +[quick-image]: https://upload.wikimedia.org/wikipedia/commons/6/6a/Sorting_quicksort_anim.gif "Quick Sort"