1 files changed, 52 insertions, 0 deletions
diff --git a/algorithms/impl/merge_sort.py b/algorithms/impl/merge_sort.py
new file mode 100644
index 0000000..fecdf78
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+++ b/algorithms/impl/merge_sort.py
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+# Copyright (c) 2015 Egor Tensin <Egor.Tensin@gmail.com>
+# This file is part of the "Sorting algorithms" project.
+# For details, see https://github.com/egor-tensin/sorting-algorithms.
+# Distributed under the MIT License.
+
+import sys
+
+from ..algorithm import SortingAlgorithm
+
+
+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:]))
+
+
+_ALGORITHMS = [
+    SortingAlgorithm('merge_sort', 'Merge sort', merge_sort),
+]
+
+
+def _parse_args(args=None):
+    if args is None:
+        args = sys.argv[1:]
+    return list(map(int, args))
+
+
+def main(args=None):
+    xs = _parse_args(args)
+    print(merge_sort(list(xs)))
+
+
+if __name__ == '__main__':
+    main()