diff --git a/BubbleSort.py b/BubbleSort.py index 5a0388855..9f3579617 100644 --- a/BubbleSort.py +++ b/BubbleSort.py @@ -1,26 +1,39 @@ +import sys -array=[]; - -# input -print ("Enter any 6 Numbers for Unsorted Array : "); -for i in range(0, 6): - n=input(); - array.append(int(n)); - -# Sorting -print("") -for i in range(0, 6): - for j in range(0,5): - if (array[j]>array[j+1]): - temp=array[j]; - array[j]=array[j+1]; - array[j+1]=temp; - -# Output -for i in range(0,6): - print(array[i]); +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 +def main(): + # Python 2's `raw_input` has been renamed to `input` in Python 3 + if sys.version_info.major < 3: + input_function = raw_input + else: + input_function = input + try: + print("Enter numbers separated by spaces:") + s = input_function() + 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)) + +if __name__ == '__main__': + print('==== Bubble Sort ====\n') + main() diff --git a/InsertionSort.py b/InsertionSort.py index e0417a755..a577c4a81 100644 --- a/InsertionSort.py +++ b/InsertionSort.py @@ -1,25 +1,40 @@ -array=[]; - -# input -print ("Enter any 6 Numbers for Unsorted Array : "); -for i in range(0, 6): - n=input(); - array.append(int(n)); - -# Sorting -print("") -for i in range(1, 6): - temp=array[i] - j=i-1; - while(j>=0 and temp= 0 and temp < int_list[j]): + int_list[j + 1] = int_list[j] + j -= 1 + int_list[j + 1] = temp + + return int_list +def main(): + # Python 2's `raw_input` has been renamed to `input` in Python 3 + if sys.version_info.major < 3: + input_function = raw_input + else: + input_function = input + + try: + print("Enter numbers separated by spaces:") + s = input_function() + 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)) + +if __name__ == '__main__': + print('==== Insertion Sort ====\n') + main() diff --git a/LinearSearch.py b/LinearSearch.py index 6180eac5a..82595eded 100644 --- a/LinearSearch.py +++ b/LinearSearch.py @@ -1,21 +1,32 @@ -def sequentialSearch(alist, item): - pos = 0 - found = False - - while pos < len(alist) and not found: - - if alist[pos] == item: - found = True - print("Found") - else: - pos = pos+1 - if found == False: - print("Not found") - return found - -print("Enter numbers seprated by space") -s = input() -numbers = list(map(int, s.split())) -trgt =int( input('enter a single number to be found in the list ')) -sequentialSearch(numbers, trgt) +import sys + +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") + + +def main(): + # Python 2's `raw_input` has been renamed to `input` in Python 3 + if sys.version_info.major < 3: + input_function = raw_input + else: + input_function = input + + try: + print("Enter numbers separated by spaces") + s = input_function() + inputs = list(map(int, s.split(' '))) + target = int(input_function('\nEnter a number to be found in list: ')) + except Exception as e: + print(e) + else: + sequential_search(inputs, target) + +if __name__ == '__main__': + print('==== Linear Search ====\n') + main() diff --git a/MergeSort.py b/MergeSort.py index 7ce144dc7..ff3a31c70 100644 --- a/MergeSort.py +++ b/MergeSort.py @@ -1,36 +1,59 @@ -def mergeSort(alist): - print("Splitting ",alist) - if len(alist)>1: - mid = len(alist)//2 - lefthalf = alist[:mid] - righthalf = alist[mid:] - mergeSort(lefthalf) - mergeSort(righthalf) - i=0 - j=0 - k=0 - while i < len(lefthalf) and j < len(righthalf): - if lefthalf[i] < righthalf[j]: - alist[k]=lefthalf[i] - i=i+1 +import sys + + +def merge_sort(alist): + print("Splitting ", alist) + if len(alist) > 1: + mid = len(alist) // 2 + left_half = alist[:mid] + right_half = alist[mid:] + merge_sort(left_half) + merge_sort(right_half) + i = j = k = 0 + + while i < len(left_half) and j < len(right_half): + if left_half[i] < right_half[j]: + alist[k] = left_half[i] + i += 1 else: - alist[k]=righthalf[j] - j=j+1 - k=k+1 + alist[k] = right_half[j] + j += 1 + k += 1 - while i < len(lefthalf): - alist[k]=lefthalf[i] - i=i+1 - k=k+1 + while i < len(left_half): + alist[k] = left_half[i] + i += 1 + k += 1 - while j < len(righthalf): - alist[k]=righthalf[j] - j=j+1 - k=k+1 - print("Merging ",alist) + while j < len(right_half): + alist[k] = right_half[j] + j += 1 + k += 1 + print("Merging ", alist) + return alist -print("Enter numbers seprated by space") -s = input() -numbers = list(map(int, s.split())) -mergeSort(numbers) +def main(): + # Python 2's `raw_input` has been renamed to `input` in Python 3 + if sys.version_info.major < 3: + input_function = raw_input + else: + input_function = input + + try: + print("Enter numbers separated by spaces:") + s = input_function() + 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 = merge_sort(inputs) + print('\nSorted list (min to max): {}'.format(sorted_input)) + +if __name__ == '__main__': + print('==== Merge Sort ====\n') + main() diff --git a/QuickSort.py b/QuickSort.py index 89db5a6a3..2d922a3de 100644 --- a/QuickSort.py +++ b/QuickSort.py @@ -1,31 +1,41 @@ +import sys -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(): + # Python 2's `raw_input` has been renamed to `input` in Python 3 + if sys.version_info.major < 3: + input_function = raw_input + else: + input_function = input + + try: + print("Enter numbers separated by spaces") + s = input_function() + 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 4c8df87ad..8fcf1a656 100644 --- a/README.md +++ b/README.md @@ -1,2 +1,89 @@ -# Python- -All Algorithms implemented in Python +# The Algorithms - Python + +### All algorithms implemented in Python (for education) + +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 Algorithms + +### Binary +Add comments here + +### Bubble +![alt text][bubble-image] + +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__ +* Worst case performance O(n^2) +* Best case performance O(n) +* Average case performance O(n^2) + +###### View the algorithm in [action][bubble-toptal] + + + +### Insertion +![alt text][insertion-image] + +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__ +* Worst case performance O(n^2) +* Best case performance O(n) +* Average case performance O(n^2) + +###### View the algorithm in [action][insertion-toptal] + + +## Merge +![alt text][merge-image] + +From [Wikipedia][merge-wiki]: In computer science, merge sort (also commonly spelled mergesort) is an efficient, general-purpose, comparison-based sorting algorithm. Most implementations produce a stable sort, which means that the implementation preserves the input order of equal elements in the sorted output. Mergesort is a divide and conquer algorithm that was invented by John von Neumann in 1945. + +__Properties__ +* Worst case performance O(n log n) +* Best case performance O(n) +* Average case performance O(n) + + +###### View the algorithm in [action][merge-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] + + +## Search Algorithms + +### Linear +Add comments here + +## Ciphers + +### Caesar +Add comments here + +[bubble-toptal]: https://www.toptal.com/developers/sorting-algorithms/bubble-sort +[bubble-wiki]: https://en.wikipedia.org/wiki/Bubble_sort +[bubble-image]: https://upload.wikimedia.org/wikipedia/commons/thumb/8/83/Bubblesort-edited-color.svg/220px-Bubblesort-edited-color.svg.png "Bubble Sort" + +[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" + +[merge-toptal]: https://www.toptal.com/developers/sorting-algorithms/merge-sort +[merge-wiki]: https://en.wikipedia.org/wiki/Merge_sort +[merge-image]: https://upload.wikimedia.org/wikipedia/commons/c/cc/Merge-sort-example-300px.gif "Merge Sort"