rearrange source files

* Add a useful `algorithms` package to provide convinient access to the
implemented algorithms.
* This allows to e.g. dynamically list available algorithms, which
greatly simplifies a lot of things.

1 files changed, 34 insertions, 0 deletions

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),
+    ]