Merge pull request raviprakashdev#22 from qwertymaden/timsort

raviprakashdev · web-flow · commit 9fbe11a9282e · 2020-10-01T20:18:22.000+05:30
Added Timsort implementation in Python
diff --git a/TimSort.py b/TimSort.py
@@ -0,0 +1,41 @@
+def timsort(array):
+    min_run = 32
+    n = len(array)
+
+    # Start by slicing and sorting small portions of the
+    # input array. The size of these slices is defined by
+    # your `min_run` size.
+    for i in range(0, n, min_run):
+        insertion_sort(array, i, min((i + min_run - 1), n - 1))
+
+    # Now you can start merging the sorted slices.
+    # Start from `min_run`, doubling the size on
+    # each iteration until you surpass the length of
+    # the array.
+    size = min_run
+    while size < n:
+        # Determine the arrays that will
+        # be merged together
+        for start in range(0, n, size * 2):
+            # Compute the `midpoint` (where the first array ends
+            # and the second starts) and the `endpoint` (where
+            # the second array ends)
+            midpoint = start + size - 1
+            end = min((start + size * 2 - 1), (n-1))
+
+            # Merge the two subarrays.
+            # The `left` array should go from `start` to
+            # `midpoint + 1`, while the `right` array should
+            # go from `midpoint + 1` to `end + 1`.
+            merged_array = merge(
+                left=array[start:midpoint + 1],
+                right=array[midpoint + 1:end + 1])
+
+            # Finally, put the merged array back into
+            # your array
+            array[start:start + len(merged_array)] = merged_array
+
+        # Each iteration should double the size of your arrays
+        size *= 2
+
+    return array
