Added working MergeSort written in Python

.gitignore

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+# Sublime Text files:
+*.sublime-*
+
+# Python compiled code:
+*.pyc
+

LICENSE

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+The MIT License (MIT)
+
+Copyright (c) 2015 x10an14
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
+

sorting_algorithms/merge_sort/python/mergesort.py

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+#! python
+# For floor division on line 16
+from __future__ import division
+# Import random number generator for testing
+import randomNumberGenerator as rndNrs
+
+
+# The recursive splitting of the arrays
+def mergesort_internal(inputlist):
+    size = len(inputlist)
+    if size < 2:
+        # If only one element in list (basecase)
+        pass
+    else:
+        # Divide
+        midpoint = size // 2
+        lower_half = mergesort_internal(inputlist[:midpoint])
+        upper_half = mergesort_internal(inputlist[midpoint:])
+
+        # Conquer
+        i, j, k = 0, 0, 0
+        while i < len(lower_half) and j < len(upper_half):
+            if upper_half[j] < lower_half[i]:
+                inputlist[k] = upper_half[j]
+                j += 1
+            else:
+                inputlist[k] = lower_half[i]
+                i += 1
+            k += 1
+
+        # If upper_half emptied first:
+        while i < len(lower_half):
+            inputlist[k] = lower_half[i]
+            i, k = i + 1, k + 1
+
+        # if lower_half emptied first:
+        while j < len(upper_half):
+            inputlist[k] = upper_half[j]
+            j, k = j + 1, k + 1
+
+    return inputlist
+
+
+def mergesort(inputlist, start=None, stop=None):
+    size = len(inputlist)
+
+    # Check first if whole array should be sorted
+    if start is None:
+        start = 0
+    if stop is None:
+        stop = size
+
+    # Check then whether indices are valid
+    if stop - start < 1 or size < start - stop:
+        return [-1]
+
+    # Perform merge sort
+    return mergesort_internal(inputlist[start:stop])
+
+# Code for executing/testing
+print("Starting...")
+
+# Get random number of elements to sort
+amountOfIntsSorted = rndNrs.random_ints(1, lower=4, upper=100)
+amountOfIntsSorted = amountOfIntsSorted[0]
+
+# Get list of random ints
+testList = rndNrs.random_ints(amountOfIntsSorted, lower=0, upper=10000)
+# testList = [2, 24, 4, 5, 3, 1]
+print(testList)
+
+print("Sorting the above list...")
+sortedList = mergesort(testList)
+
+print("Sorted list:")
+print(sortedList)
+
+# Check if list was sorted correctly, by using python's sorted() as comparison
+correctList = sorted(testList)
+correctlySorted = True
+for x in xrange(amountOfIntsSorted):
+    if sortedList[x] != correctList[x]:
+        correctlySorted = False
+
+if correctlySorted:
+    print("List was sorted correctly!!! =D")
+else:
+    print("List was sorted incorrectly!!! =(")

sorting_algorithms/merge_sort/python/randomNumberGenerator.py

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+#! python
+import random
+
+# From:
+# http://bytes.com/topic/python/answers/829129-generate-random-list-integers
+
+
+def random_ints(amount, lower=0, upper=100):
+    return [random.randrange(lower, upper + 1) for i in range(amount)]
+
+# print random_ints(100)