From ebf993535a30db5cf03133c504b06b4c0bf38797 Mon Sep 17 00:00:00 2001
From: BuildTools <Tobias-Hettler@protonmail.com>
Date: Sat, 22 May 2021 11:40:14 +0200
Subject: [PATCH 1/2] Implemented MSD radix sort algorithm inplace

---
 sorts/msd_radix_sort.py | 79 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 79 insertions(+)

diff --git a/sorts/msd_radix_sort.py b/sorts/msd_radix_sort.py
index ee152bbc696a..af4f8f652ca3 100644
--- a/sorts/msd_radix_sort.py
+++ b/sorts/msd_radix_sort.py
@@ -74,6 +74,85 @@ def _msd_radix_sort(list_of_ints: List[int], bit_position: int) -> List[int]:
     return res
 
 
+def msd_radix_sort_inplace(list_of_ints: List[int]):
+    """
+    Inplace implementation of the MSD radix sort algorithm.
+    Sorts based on the binary representation of the integers.
+    >>> lst = [1, 345, 23, 89, 0, 3]
+    >>> msd_radix_sort_inplace(lst)
+    >>> lst == sorted(lst)
+    True
+    >>> lst = [1, 43, 0, 0, 0, 24, 3, 3]
+    >>> msd_radix_sort_inplace(lst)
+    >>> lst == sorted(lst)
+    True
+    >>> lst = []
+    >>> msd_radix_sort_inplace(lst)
+    >>> lst == []
+    True
+    >>> lst = [-1, 34, 23, 4, -42]
+    >>> msd_radix_sort_inplace(lst)
+    Traceback (most recent call last):
+    ...
+    ValueError: All numbers must be positive
+    """
+
+    length = len(list_of_ints)
+    if not list_of_ints or length == 1:
+        return
+
+    if min(list_of_ints) < 0:
+        raise ValueError("All numbers must be positive")
+
+    most_bits = max(len(bin(x)[2:]) for x in list_of_ints)
+    _msd_radix_sort_inplace(list_of_ints, most_bits, 0, length)
+
+
+def _msd_radix_sort_inplace(list_of_ints: List[int], bit_position: int,
+                            begin_index: int, end_index: int):
+    """
+    Sort the given list based on the bit at bit_position. Numbers with a
+    0 at that position will be at the start of the list, numbers with a
+    1 at the end.
+    >>> lst = [45, 2, 32, 24, 534, 2932]
+    >>> _msd_radix_sort_inplace(lst, 1, 0, 3)
+    >>> lst == [32, 2, 45, 24, 534, 2932]
+    True
+    >>> lst = [0, 2, 1, 3, 12, 10, 4, 90, 54, 2323, 756]
+    >>> _msd_radix_sort_inplace(lst, 2, 4, 7)
+    >>> lst == [0, 2, 1, 3, 12, 4, 10, 90, 54, 2323, 756]
+    True
+    """
+    if bit_position == 0 or end_index - begin_index <= 1:
+        return
+
+    bit_position -= 1
+
+    i = begin_index
+    j = end_index - 1
+    while i <= j:
+        changed = False
+        if not ((list_of_ints[i] >> bit_position) & 1):
+            # found zero at the beginning
+            i += 1
+            changed = True
+        if (list_of_ints[j] >> bit_position) & 1:
+            # found one at the end
+            j -= 1
+            changed = True
+
+        if changed:
+            continue
+
+        list_of_ints[i], list_of_ints[j] = list_of_ints[j], list_of_ints[i]
+        j -= 1
+        if not j == i:
+            i += 1
+
+    _msd_radix_sort_inplace(list_of_ints, bit_position, begin_index, i)
+    _msd_radix_sort_inplace(list_of_ints, bit_position, i, end_index)
+
+
 if __name__ == "__main__":
     import doctest
 

From 78c210e5e46435a63fb4eac091b71e7bdfb8162e Mon Sep 17 00:00:00 2001
From: BuildTools <Tobias-Hettler@protonmail.com>
Date: Sat, 22 May 2021 11:48:31 +0200
Subject: [PATCH 2/2] Fixed formatting

---
 sorts/msd_radix_sort.py | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/sorts/msd_radix_sort.py b/sorts/msd_radix_sort.py
index af4f8f652ca3..4c3cea30ef68 100644
--- a/sorts/msd_radix_sort.py
+++ b/sorts/msd_radix_sort.py
@@ -108,8 +108,9 @@ def msd_radix_sort_inplace(list_of_ints: List[int]):
     _msd_radix_sort_inplace(list_of_ints, most_bits, 0, length)
 
 
-def _msd_radix_sort_inplace(list_of_ints: List[int], bit_position: int,
-                            begin_index: int, end_index: int):
+def _msd_radix_sort_inplace(
+    list_of_ints: List[int], bit_position: int, begin_index: int, end_index: int
+):
     """
     Sort the given list based on the bit at bit_position. Numbers with a
     0 at that position will be at the start of the list, numbers with a