added timsort.py

Author: theycallmemac

sorts/timsort.py

@@ -0,0 +1,68 @@
+def binary_search(the_array, item, start, end):
+    if start == end:
+        if the_array[start] > item:
+            return start
+        else:
+            return start + 1
+    if start > end:
+        return start
+
+    mid = (start + end)/ 2
+    if the_array[mid] < item:
+        return binary_search(the_array, item, mid + 1, end)
+    elif the_array[mid] > item:
+        return binary_search(the_array, item, start, mid - 1)
+    else:
+        return mid
+
+
+"""
+Insertion sort that the heap sort uses if the array size is small or if
+the size of the "run" is small
+"""
+def insertion_sort(the_array):
+    l = len(the_array)
+    for index in range(1, l):
+        value = the_array[index]
+        pos = binary_search(the_array, value, 0, index - 1)
+        the_array = the_array[:pos] + [value] + the_array[pos:index] + the_array[index+1:]
+    return the_array
+
+def merge(left, right):
+    """Takes two sorted lists and returns a single sorted list by comparing the
+    elements one at a time.
+    [1, 2, 3, 4, 5, 6]
+    """
+    if not left:
+        return right
+    if not right:
+        return left
+    if left[0] < right[0]:
+        return [left[0]] + merge(left[1:], right)
+    return [right[0]] + merge(left, right[1:])
+
+
+def timsort(the_array):
+    runs, sorted_runs = [], []
+    l = len(the_array)
+    new_run = [the_array[0]]
+    for i in range(1, l):
+        if i == l-1:
+            new_run.append(the_array[i])
+            runs.append(new_run)
+            break
+        if the_array[i] < the_array[i-1]:
+            if not new_run:
+                runs.append([the_array[i-1]])
+                new_run.append(the_array[i])
+            else:
+                runs.append(new_run)
+                new_run = []
+        else:
+            new_run.append(the_array[i])
+    for each in runs:
+        sorted_runs.append(insertion_sort(each))
+    sorted_array = []
+    for run in sorted_runs:
+        sorted_array = merge(sorted_array, run)
+print(sorted_array)