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-rw-r--r--algorithms/__init__.py0
-rw-r--r--algorithms/algorithm.py25
-rw-r--r--algorithms/impl/__init__.py29
-rw-r--r--algorithms/impl/bubble_sort.py39
-rw-r--r--algorithms/impl/heapsort.py59
-rw-r--r--algorithms/impl/insertion_sort.py20
-rw-r--r--algorithms/impl/merge_sort.py34
-rw-r--r--algorithms/impl/quicksort.py74
-rw-r--r--algorithms/impl/selection_sort.py22
-rw-r--r--algorithms/registry.py17
10 files changed, 319 insertions, 0 deletions
diff --git a/algorithms/__init__.py b/algorithms/__init__.py
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/algorithms/__init__.py
diff --git a/algorithms/algorithm.py b/algorithms/algorithm.py
new file mode 100644
index 0000000..322a51f
--- /dev/null
+++ b/algorithms/algorithm.py
@@ -0,0 +1,25 @@
+# Copyright 2016 Egor Tensin <Egor.Tensin@gmail.com>
+# This file is licensed under the terms of the MIT License.
+# See LICENSE.txt for details.
+
+class Algorithm:
+ def __init__(self, codename, display_name, f):
+ self._codename = codename
+ self._display_name = display_name
+ self._f = f
+
+ def get_codename(self):
+ return self._codename
+
+ def get_display_name(self):
+ return self._display_name
+
+ def get_function(self):
+ return self._f
+
+ def __str__(self):
+ return self.get_display_name()
+
+class SortingAlgorithm(Algorithm):
+ def __init__(self, codename, display_name, f):
+ super().__init__(codename, display_name, f)
diff --git a/algorithms/impl/__init__.py b/algorithms/impl/__init__.py
new file mode 100644
index 0000000..29cd51c
--- /dev/null
+++ b/algorithms/impl/__init__.py
@@ -0,0 +1,29 @@
+# Copyright 2016 Egor Tensin <Egor.Tensin@gmail.com>
+# This file is licensed under the terms of the MIT License.
+# See LICENSE.txt for details.
+
+_ALL_ALGORITHMS = {}
+
+def _refresh_algorithms():
+ _ALGORITHMS_NAME = '_ALGORITHMS'
+ global _ALL_ALGORITHMS
+ _ALL_ALGORITHMS = {}
+
+ from algorithms.algorithm import Algorithm
+
+ from importlib import import_module
+ import os.path
+ from pkgutil import iter_modules
+
+ for _, module_name, is_pkg in iter_modules([os.path.dirname(__file__)]):
+ if is_pkg:
+ continue
+ module = import_module('.' + module_name, __package__)
+ if hasattr(module, _ALGORITHMS_NAME):
+ module_algorithms = getattr(module, _ALGORITHMS_NAME)
+ for algorithm in module_algorithms:
+ assert isinstance(algorithm, Algorithm)
+ assert algorithm.get_codename() not in _ALL_ALGORITHMS
+ _ALL_ALGORITHMS[algorithm.get_codename()] = algorithm
+
+_refresh_algorithms()
diff --git a/algorithms/impl/bubble_sort.py b/algorithms/impl/bubble_sort.py
new file mode 100644
index 0000000..2abfc43
--- /dev/null
+++ b/algorithms/impl/bubble_sort.py
@@ -0,0 +1,39 @@
+# Copyright 2015 Egor Tensin <Egor.Tensin@gmail.com>
+# This file is licensed under the terms of the MIT License.
+# See LICENSE.txt for details.
+
+def bubble_sort(xs):
+ while True:
+ swapped = False
+ for i in range(1, len(xs)):
+ if xs[i - 1] > xs[i]:
+ xs[i], xs[i - 1] = xs[i - 1], xs[i]
+ swapped = True
+ if not swapped:
+ break
+ return xs
+
+def bubble_sort_optimized(xs):
+ n = len(xs)
+ while True:
+ new_n = 0
+ for i in range(1, n):
+ if xs[i - 1] > xs[i]:
+ xs[i], xs[i - 1] = xs[i - 1], xs[i]
+ new_n = i
+ n = new_n
+ if not n:
+ break
+ return xs
+
+if __name__ == '__main__':
+ import sys
+ xs = list(map(int, sys.argv[1:]))
+ print(bubble_sort(list(xs)))
+ print(bubble_sort_optimized(list(xs)))
+else:
+ from algorithms.algorithm import SortingAlgorithm
+ _ALGORITHMS = [
+ SortingAlgorithm('bubble_sort', 'Bubble sort', bubble_sort),
+ SortingAlgorithm('bubble_sort_optimized', 'Bubble sort (optimized)', bubble_sort_optimized),
+ ]
diff --git a/algorithms/impl/heapsort.py b/algorithms/impl/heapsort.py
new file mode 100644
index 0000000..db3b6bd
--- /dev/null
+++ b/algorithms/impl/heapsort.py
@@ -0,0 +1,59 @@
+# Copyright 2015 Egor Tensin <Egor.Tensin@gmail.com>
+# This file is licensed under the terms of the MIT License.
+# See LICENSE.txt for details.
+
+# Disclaimer: implemented in the most literate way.
+
+def heapsort(xs):
+ _heapify(xs)
+ first, last = 0, len(xs) - 1
+ for end in range(last, first, -1):
+ xs[end], xs[first] = xs[first], xs[end]
+ _siftdown(xs, first, end - 1)
+ return xs
+
+# In a heap stored in a zero-based array,
+# left_child = node * 2 + 1
+# right_child = node * 2 + 2
+# parent = (node - 1) // 2
+
+def _get_parent(node):
+ return (node - 1) // 2
+
+def _get_left_child(node):
+ return node * 2 + 1
+
+def _get_right_child(node):
+ return node * 2 + 2
+
+def _heapify(xs):
+ last = len(xs) - 1
+ first_parent, last_parent = 0, _get_parent(last)
+ for parent in range(last_parent, first_parent - 1, -1):
+ _siftdown(xs, parent, last)
+
+def _siftdown(xs, start, end):
+ root = start
+ while True:
+ # We swap if there is at least one child
+ child = _get_left_child(root)
+ if child > end:
+ break
+ # If there are two children, select the minimum
+ right_child = _get_right_child(root)
+ if right_child <= end and xs[child] < xs[right_child]:
+ child = right_child
+ if xs[root] < xs[child]:
+ xs[root], xs[child] = xs[child], xs[root]
+ root = child
+ else:
+ break
+
+if __name__ == '__main__':
+ import sys
+ print(heapsort(list(map(int, sys.argv[1:]))))
+else:
+ from algorithms.algorithm import SortingAlgorithm
+ _ALGORITHMS = [
+ SortingAlgorithm('heapsort', 'Heapsort', heapsort),
+ ]
diff --git a/algorithms/impl/insertion_sort.py b/algorithms/impl/insertion_sort.py
new file mode 100644
index 0000000..f671712
--- /dev/null
+++ b/algorithms/impl/insertion_sort.py
@@ -0,0 +1,20 @@
+# Copyright 2015 Egor Tensin <Egor.Tensin@gmail.com>
+# This file is licensed under the terms of the MIT License.
+# See LICENSE.txt for details.
+
+def insertion_sort(xs):
+ for i in range(1, len(xs)):
+ j = i
+ while j > 0 and xs[j - 1] > xs[j]:
+ xs[j], xs[j - 1] = xs[j - 1], xs[j]
+ j -= 1
+ return xs
+
+if __name__ == '__main__':
+ import sys
+ print(insertion_sort(list(map(int, sys.argv[1:]))))
+else:
+ from algorithms.algorithm import SortingAlgorithm
+ _ALGORITHMS = [
+ SortingAlgorithm('insertion_sort', 'Insertion sort', insertion_sort),
+ ]
diff --git a/algorithms/impl/merge_sort.py b/algorithms/impl/merge_sort.py
new file mode 100644
index 0000000..9fa96ec
--- /dev/null
+++ b/algorithms/impl/merge_sort.py
@@ -0,0 +1,34 @@
+# Copyright 2015 Egor Tensin <Egor.Tensin@gmail.com>
+# This file is licensed under the terms of the MIT License.
+# See LICENSE.txt for details.
+
+def merge(left, right):
+ result = []
+ l, r = 0, 0
+ while l < len(left) and r < len(right):
+ if left[l] <= right[r]:
+ result.append(left[l])
+ l += 1
+ else:
+ result.append(right[r])
+ r += 1
+ if left:
+ result.extend(left[l:])
+ if right:
+ result.extend(right[r:])
+ return result
+
+def merge_sort(xs):
+ if len(xs) < 2:
+ return xs
+ mid = len(xs) // 2
+ return merge(merge_sort(xs[:mid]), merge_sort(xs[mid:]))
+
+if __name__ == '__main__':
+ import sys
+ print(merge_sort(list(map(int, sys.argv[1:]))))
+else:
+ from algorithms.algorithm import SortingAlgorithm
+ _ALGORITHMS = [
+ SortingAlgorithm('merge_sort', 'Merge sort', merge_sort),
+ ]
diff --git a/algorithms/impl/quicksort.py b/algorithms/impl/quicksort.py
new file mode 100644
index 0000000..32100b0
--- /dev/null
+++ b/algorithms/impl/quicksort.py
@@ -0,0 +1,74 @@
+# Copyright 2015 Egor Tensin <Egor.Tensin@gmail.com>
+# This file is licensed under the terms of the MIT License.
+# See LICENSE.txt for details.
+
+from random import randrange
+
+def _partition(xs, beg, end, select_pivot):
+ pivot = select_pivot(xs, beg, end)
+ xs[pivot], xs[end] = xs[end], xs[pivot]
+ for i in range(beg, end):
+ if xs[i] <= xs[end]:
+ xs[i], xs[beg] = xs[beg], xs[i]
+ beg += 1
+ xs[beg], xs[end] = xs[end], xs[beg]
+ return beg
+
+def _quicksort(xs, beg, end, select_pivot):
+ if beg < end:
+ pivot = _partition(xs, beg, end, select_pivot)
+ _quicksort(xs, beg, pivot - 1, select_pivot)
+ _quicksort(xs, pivot + 1, end, select_pivot)
+
+def _select_first(xs, beg, end):
+ return beg
+
+def _select_second(xs, beg, end):
+ return beg + 1
+
+def _select_middle(xs, beg, end):
+ return (beg + end) // 2
+
+def _select_last(xs, beg, end):
+ return end
+
+def _select_random(xs, beg, end):
+ return randrange(beg, end + 1)
+
+def quicksort_first(xs):
+ _quicksort(xs, 0, len(xs) - 1, _select_first)
+ return xs
+
+def quicksort_second(xs):
+ _quicksort(xs, 0, len(xs) - 1, _select_second)
+ return xs
+
+def quicksort_middle(xs):
+ _quicksort(xs, 0, len(xs) - 1, _select_middle)
+ return xs
+
+def quicksort_last(xs):
+ _quicksort(xs, 0, len(xs) - 1, _select_last)
+ return xs
+
+def quicksort_random(xs):
+ _quicksort(xs, 0, len(xs) - 1, _select_random)
+ return xs
+
+if __name__ == '__main__':
+ import sys
+ xs = list(map(int, sys.argv[1:]))
+ print(quicksort_first(list(xs)))
+ print(quicksort_second(list(xs)))
+ print(quicksort_middle(list(xs)))
+ print(quicksort_last(list(xs)))
+ print(quicksort_random(list(xs)))
+else:
+ from algorithms.algorithm import SortingAlgorithm
+ _ALGORITHMS = [
+ SortingAlgorithm('quicksort_first', 'Quicksort (first element as pivot)', quicksort_first),
+ SortingAlgorithm('quicksort_second', 'Quicksort (second element as pivot)', quicksort_second),
+ SortingAlgorithm('quicksort_middle', 'Quicksort (middle element as pivot)', quicksort_middle),
+ SortingAlgorithm('quicksort_last', 'Quicksort (last element as pivot)', quicksort_last),
+ SortingAlgorithm('quicksort_random', 'Quicksort (random element as pivot)', quicksort_random),
+ ]
diff --git a/algorithms/impl/selection_sort.py b/algorithms/impl/selection_sort.py
new file mode 100644
index 0000000..d48c058
--- /dev/null
+++ b/algorithms/impl/selection_sort.py
@@ -0,0 +1,22 @@
+# Copyright 2015 Egor Tensin <Egor.Tensin@gmail.com>
+# This file is licensed under the terms of the MIT License.
+# See LICENSE.txt for details.
+
+def selection_sort(xs):
+ for i in range(len(xs) - 1):
+ min_i = i
+ for j in range(i + 1, len(xs)):
+ if xs[j] < xs[min_i]:
+ min_i = j
+ if min_i != i:
+ xs[i], xs[min_i] = xs[min_i], xs[i]
+ return xs
+
+if __name__ == '__main__':
+ import sys
+ print(selection_sort(list(map(int, sys.argv[1:]))))
+else:
+ from algorithms.algorithm import SortingAlgorithm
+ _ALGORITHMS = [
+ SortingAlgorithm('selection', 'Selection sort', selection_sort),
+ ]
diff --git a/algorithms/registry.py b/algorithms/registry.py
new file mode 100644
index 0000000..8f0469d
--- /dev/null
+++ b/algorithms/registry.py
@@ -0,0 +1,17 @@
+# Copyright 2016 Egor Tensin <Egor.Tensin@gmail.com>
+# This file is licensed under the terms of the MIT License.
+# See LICENSE.txt for details.
+
+import algorithms.impl
+
+def refresh_algorithms():
+ algorithms.impl._refresh_algorithms()
+
+def get_codenames():
+ return algorithms.impl._ALL_ALGORITHMS.keys()
+
+def iter_algorithms():
+ return iter(algorithms.impl._ALL_ALGORITHMS.values())
+
+def get(codename):
+ return algorithms.impl._ALL_ALGORITHMS[codename]
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-24 05:11:51 +0000