From fd43c3832041769e11d42d6bac6300f549ed4d33 Mon Sep 17 00:00:00 2001
From: Sumanth Palla <64864074+sumanthpalla@users.noreply.github.com>
Date: Mon, 7 Jun 2021 18:27:16 +0530
Subject: [PATCH] chore(Python): added Merge Sort algorithm (#329)

Co-authored-by: Sumanth <sumanthpalla05@gmail.com>
Co-authored-by: Arsenic <54987647+Arsenic-ATG@users.noreply.github.com>
---
 algorithms/Python/README.md             |  1 +
 algorithms/Python/sorting/merge_sort.py | 34 +++++++++++++++++++++++++
 2 files changed, 35 insertions(+)
 create mode 100644 algorithms/Python/sorting/merge_sort.py

diff --git a/algorithms/Python/README.md b/algorithms/Python/README.md
index f9c50fa4..d715cdf0 100644
--- a/algorithms/Python/README.md
+++ b/algorithms/Python/README.md
@@ -38,6 +38,7 @@
 6. [Heap Sort](sorting/heap-sort.py)
 7. [Radix Sort](sorting/radix-sort.py)
 8. [Shell Sort](sorting/shell-sort.py)
+9. [Merge sort](sorting/merge_sort.py)
 
 ## Strings
 
diff --git a/algorithms/Python/sorting/merge_sort.py b/algorithms/Python/sorting/merge_sort.py
new file mode 100644
index 00000000..cb885ca3
--- /dev/null
+++ b/algorithms/Python/sorting/merge_sort.py
@@ -0,0 +1,34 @@
+## Implementation of merge sort 
+## Merge Sort is a recursive algorithm which sorts the list by divide and conquer approach
+def merge_sort(list):
+    # if list size <= 1, the list is anyway sorted! :)
+    if len(list)==1: return list
+    #splitting the list into half 
+    mid = len(list)//2 # integer division
+    l = list[:mid]
+    r = list[mid:]
+    merge_sort(l) # recursive calling of left part of list 
+    merge_sort(r) # recursive calling of right part of list
+    #merging the left and right parts
+    i=j=k=0
+    while(i<len(l)and j<len(r)): 
+        if l[i]<=r[j]:
+            list[k]=l[i]
+            i+=1
+        else:
+            list[k]=r[j]
+            j+=1
+        k+=1
+    while(i<len(l)):
+        list[k]=l[i]
+        i+=1
+        k+=1
+    while(j<len(r)):
+        list[k]=r[j]
+        j+=1
+        k+=1
+    return list
+##### main ###
+if __name__ == '__main__':
+    arr = [10, 1, 6, 256, 2, 53, 235, 53, 1, 7, 0, -23, 23]
+    print("Sorted Array:", merge_sort(arr))