From d8810951c55212681c6536afa6f3e8170bef40cf Mon Sep 17 00:00:00 2001
From: Prachi <prachidadhich49@gmail.com>
Date: Wed, 13 Oct 2021 11:10:56 +0530
Subject: [PATCH 1/6] updated MergeSort.py and algorithm.md

---
 DSA                                    |  1 +
 sorting/Merge Sort/Python/mergesort.py | 42 ++++++++++++++++++++++++++
 sorting/Merge Sort/algorithm.md        | 16 ++++++++++
 3 files changed, 59 insertions(+)
 create mode 160000 DSA
 create mode 100644 sorting/Merge Sort/Python/mergesort.py
 create mode 100644 sorting/Merge Sort/algorithm.md

diff --git a/DSA b/DSA
new file mode 160000
index 0000000..8edf746
--- /dev/null
+++ b/DSA
@@ -0,0 +1 @@
+Subproject commit 8edf7466498f13063b693a3bd5eab703c9bd7cad
diff --git a/sorting/Merge Sort/Python/mergesort.py b/sorting/Merge Sort/Python/mergesort.py
new file mode 100644
index 0000000..8d3c715
--- /dev/null
+++ b/sorting/Merge Sort/Python/mergesort.py	
@@ -0,0 +1,42 @@
+def merge(array,beg,m,end):
+    
+
+    temp = [0]* (end-beg+1)
+    i,j,k = beg, m+1, 0
+    
+
+    while i<=m and j<=end:
+        if array[i]<=array[j]:
+            temp[k] = array[i]
+            k+=1
+            i+=1
+        else:
+            temp[k] = array[j]
+            k+=1
+            j+=1
+        
+
+    while i <= m:
+        temp[k] = array[i]
+        i += 1
+        k += 1
+ 
+    while j <= end:
+        temp[k] = array[j]
+        j += 1
+        k += 1      
+
+    for i in range(beg,end+1):
+        array[i] = temp[i-beg]      
+
+def Merge_sort(array, beg, end):
+    if beg<end:
+        m = (beg+end)/2
+        Merge_sort(array,beg,m)
+        Merge_sort(array,m+1,end)
+        merge(array,beg,m,end)
+
+#Sample Input: 5 14 35 20 7 2
+#Sample Output: 2 5 7 14 20 35
+#Time Complexity: θ(nLogn) in all cases(worst, average and best)
+#Space Complexity: O(n)  
\ No newline at end of file
diff --git a/sorting/Merge Sort/algorithm.md b/sorting/Merge Sort/algorithm.md
new file mode 100644
index 0000000..7a0ee77
--- /dev/null
+++ b/sorting/Merge Sort/algorithm.md	
@@ -0,0 +1,16 @@
+## Merge Sort
+### Merge Sort is a very efficient sorting algorithm. It uses Divide and Conquer principle to sort the elements. It divides the list into two equal halves. The sub-lists are divided again and again until each sublist consists of a single element.Then merge sublists in a way that results in a sorted list.
+![This is an image](https://media.geeksforgeeks.org/wp-content/cdn-uploads/Merge-Sort-Tutorial.png)     
+
+## Algorithm
+```
+Merge_sort(array,start,end)
+Step 1: if start<end
+Step 2:set m = (start+end)/2
+Step 3: Merge_sort(array,start,m)
+Step 4: Merge_sort(array,m+1,end)
+Step 5: merge(array,start,m,end)
+Step 6: end of if
+Step 7: END of Merge_sort
+Step 8:Exit
+```
\ No newline at end of file

From a8a2392a183cf21b5848677d83b83f1164fc4668 Mon Sep 17 00:00:00 2001
From: PrachiDadhich <60838285+PrachiDadhich@users.noreply.github.com>
Date: Wed, 13 Oct 2021 13:06:20 +0530
Subject: [PATCH 2/6] Update mergesort.py

---
 sorting/Merge Sort/Python/mergesort.py | 32 +++++++++++---------------
 1 file changed, 14 insertions(+), 18 deletions(-)

diff --git a/sorting/Merge Sort/Python/mergesort.py b/sorting/Merge Sort/Python/mergesort.py
index 8d3c715..74ab339 100644
--- a/sorting/Merge Sort/Python/mergesort.py	
+++ b/sorting/Merge Sort/Python/mergesort.py	
@@ -1,20 +1,16 @@
-def merge(array,beg,m,end):
+def merge(array: [int], beg: int, m: int, end: int):
+    temp = [0]* (end - beg + 1)
+    i,j,k = beg, m + 1, 0
     
-
-    temp = [0]* (end-beg+1)
-    i,j,k = beg, m+1, 0
-    
-
-    while i<=m and j<=end:
-        if array[i]<=array[j]:
+    while i <= m and j <= end:
+        if array[i] <= array[j]:
             temp[k] = array[i]
-            k+=1
-            i+=1
+            k += 1
+            i += 1
         else:
             temp[k] = array[j]
-            k+=1
-            j+=1
-        
+            k += 1
+            j += 1     
 
     while i <= m:
         temp[k] = array[i]
@@ -27,11 +23,11 @@ def merge(array,beg,m,end):
         k += 1      
 
     for i in range(beg,end+1):
-        array[i] = temp[i-beg]      
+        array[i] = temp[i - beg]      
 
-def Merge_sort(array, beg, end):
-    if beg<end:
-        m = (beg+end)/2
+def Merge_sort(array: [int], beg: int, end: int):
+    if beg < end:
+        m = (beg + end)/2
         Merge_sort(array,beg,m)
         Merge_sort(array,m+1,end)
         merge(array,beg,m,end)
@@ -39,4 +35,4 @@ def Merge_sort(array, beg, end):
 #Sample Input: 5 14 35 20 7 2
 #Sample Output: 2 5 7 14 20 35
 #Time Complexity: θ(nLogn) in all cases(worst, average and best)
-#Space Complexity: O(n)  
\ No newline at end of file
+#Space Complexity: O(n)  

From a89cf53fa57bb0f07cba44d4067dd3dc26ccfce7 Mon Sep 17 00:00:00 2001
From: PrachiDadhich <60838285+PrachiDadhich@users.noreply.github.com>
Date: Wed, 13 Oct 2021 20:56:36 +0530
Subject: [PATCH 3/6] Rename mergesort.py to MergeSort.py

---
 sorting/Merge Sort/Python/{mergesort.py => MergeSort.py} | 0
 1 file changed, 0 insertions(+), 0 deletions(-)
 rename sorting/Merge Sort/Python/{mergesort.py => MergeSort.py} (100%)

diff --git a/sorting/Merge Sort/Python/mergesort.py b/sorting/Merge Sort/Python/MergeSort.py
similarity index 100%
rename from sorting/Merge Sort/Python/mergesort.py
rename to sorting/Merge Sort/Python/MergeSort.py

From 81f7824dce463c8e37929d8b97ae15eef4bd30c7 Mon Sep 17 00:00:00 2001
From: PrachiDadhich <60838285+PrachiDadhich@users.noreply.github.com>
Date: Wed, 13 Oct 2021 21:31:46 +0530
Subject: [PATCH 4/6] Rename sorting/Merge Sort/algorithm.md to Sorting/Merge
 Sort/algorithm.md

---
 {sorting => Sorting}/Merge Sort/algorithm.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
 rename {sorting => Sorting}/Merge Sort/algorithm.md (99%)

diff --git a/sorting/Merge Sort/algorithm.md b/Sorting/Merge Sort/algorithm.md
similarity index 99%
rename from sorting/Merge Sort/algorithm.md
rename to Sorting/Merge Sort/algorithm.md
index 7a0ee77..a08f3d4 100644
--- a/sorting/Merge Sort/algorithm.md	
+++ b/Sorting/Merge Sort/algorithm.md	
@@ -13,4 +13,4 @@ Step 5: merge(array,start,m,end)
 Step 6: end of if
 Step 7: END of Merge_sort
 Step 8:Exit
-```
\ No newline at end of file
+```

From 650e9c39f23b7c6fa1e39d853836624aeb334f82 Mon Sep 17 00:00:00 2001
From: PrachiDadhich <60838285+PrachiDadhich@users.noreply.github.com>
Date: Wed, 13 Oct 2021 21:33:29 +0530
Subject: [PATCH 5/6] Rename sorting/Merge Sort/Python/MergeSort.py to
 Sorting/Merge Sort/Python/MergeSort.py

---
 {sorting => Sorting}/Merge Sort/Python/MergeSort.py | 0
 1 file changed, 0 insertions(+), 0 deletions(-)
 rename {sorting => Sorting}/Merge Sort/Python/MergeSort.py (100%)

diff --git a/sorting/Merge Sort/Python/MergeSort.py b/Sorting/Merge Sort/Python/MergeSort.py
similarity index 100%
rename from sorting/Merge Sort/Python/MergeSort.py
rename to Sorting/Merge Sort/Python/MergeSort.py

From 6ad6dc8a74098926768bb6ac550b43bb89cb723c Mon Sep 17 00:00:00 2001
From: Prachi <prachidadhich49@gmail.com>
Date: Sun, 17 Oct 2021 23:48:12 +0530
Subject: [PATCH 6/6] Added Preorder traversal

---
 .../Python/PreorderTraversal.py               | 45 +++++++++++++++++++
 1 file changed, 45 insertions(+)
 create mode 100644 Traversal Algorithms/Tree Traversals/Preorder Traveral - Binary Tree/Python/PreorderTraversal.py

diff --git a/Traversal Algorithms/Tree Traversals/Preorder Traveral - Binary Tree/Python/PreorderTraversal.py b/Traversal Algorithms/Tree Traversals/Preorder Traveral - Binary Tree/Python/PreorderTraversal.py
new file mode 100644
index 0000000..3350714
--- /dev/null
+++ b/Traversal Algorithms/Tree Traversals/Preorder Traveral - Binary Tree/Python/PreorderTraversal.py	
@@ -0,0 +1,45 @@
+
+# Sample Input::
+# Input Tree :
+#   1
+#  / \
+# 6   5
+#    /
+#   2
+
+# Output: [1, 6, 5, 2]
+
+# Recursive Code
+# Binary Tree representation
+# class TreeNode:
+
+#    def __init__(self,value):
+#        self.value = value
+#        self.left = None
+#        self.right = None
+
+def preorder(root):
+    res = []
+
+    preorderTraversal(root, res)
+    return res
+
+def preorderTraversal(root, res):
+
+    if root is None:
+        return 
+
+    res.append(root.value)
+
+    preorderTraversal(root.left, res)
+
+    preorderTraversal(root.right, res)
+
+    return
+
+# Time Complexity: O(n)
+# Space Complexity: O(n)
+
+
+
+