From 4186fba7518c475c023fc8be1c0d2450e21ee15c Mon Sep 17 00:00:00 2001
From: kmk028 <kmk028@users.noreply.github.com>
Date: Sun, 27 Sep 2020 18:17:19 -0700
Subject: [PATCH 1/3] RingBuffer completed

---
 ring_buffer/ring_buffer.py | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/ring_buffer/ring_buffer.py b/ring_buffer/ring_buffer.py
index 37e9fb0dd..d5a37934d 100644
--- a/ring_buffer/ring_buffer.py
+++ b/ring_buffer/ring_buffer.py
@@ -1,9 +1,14 @@
 class RingBuffer:
     def __init__(self, capacity):
-        pass
+        self.capacity = capacity
+        self.storage = [None]*capacity
+        self.curr = 0
 
     def append(self, item):
-        pass
+        self.storage[self.curr] = item 
+        self.curr += 1
+        if self.curr == self.capacity:
+            self.curr=0
 
     def get(self):
-        pass
\ No newline at end of file
+        return [x for x in self.storage if x is not None]
\ No newline at end of file

From 753b0cc6a7925cf5d622c9f2656f3850e944c6db Mon Sep 17 00:00:00 2001
From: kmk028 <kmk028@users.noreply.github.com>
Date: Sun, 27 Sep 2020 18:45:56 -0700
Subject: [PATCH 2/3] RunTime optimization using BST

---
 names/BST.py   | 38 ++++++++++++++++++++++++++++++++++++++
 names/names.py | 28 ++++++++++++++++++++++------
 2 files changed, 60 insertions(+), 6 deletions(-)
 create mode 100644 names/BST.py

diff --git a/names/BST.py b/names/BST.py
new file mode 100644
index 000000000..3393f403a
--- /dev/null
+++ b/names/BST.py
@@ -0,0 +1,38 @@
+class BSTNode:
+    def __init__(self, value):
+        self.value = value
+        self.left = None
+        self.right = None
+
+    # Insert the given value into the tree
+    def insert(self, value):
+        # if root is not empty and value is greater than root, place value to right of root
+        if (value >= self.value) and (self.right != None):
+            self.right.insert(value)
+        # if root is empty and value is greater than root, create a node and place value to right of root
+        if (value >= self.value) and (self.right == None):
+            new_node = BSTNode(value)
+            self.right = new_node
+        # if root is not empty and value is lesser than root, place value to right of root
+        if (value < self.value) and (self.left != None):
+            self.left.insert(value)
+        # if root is empty and value is lesser than root, create a node and place value to left of root
+        if (value < self.value) and (self.left == None):
+            new_node = BSTNode(value)
+            self.left = new_node
+
+    # Return True if the tree contains the value
+    # False if it does not
+    def contains(self, target):
+        if target == self.value:
+            return True
+        if (target>self.value):
+            if self.right is not None:
+                return self.right.contains(target)
+            else:
+                return False
+        if (target<self.value):
+            if self.left is not None:
+                return self.left.contains(target)
+            else:
+                return False
\ No newline at end of file
diff --git a/names/names.py b/names/names.py
index ea158997f..a806ba07e 100644
--- a/names/names.py
+++ b/names/names.py
@@ -1,5 +1,5 @@
 import time
-
+from BST import BSTNode
 start_time = time.time()
 
 f = open('names_1.txt', 'r')
@@ -12,11 +12,27 @@
 
 duplicates = []  # Return the list of duplicates in this data structure
 
-# Replace the nested for loops below with your improvements
-for name_1 in names_1:
-    for name_2 in names_2:
-        if name_1 == name_2:
-            duplicates.append(name_1)
+# # Replace the nested for loops below with your improvements
+# for name_1 in names_1:
+#     for name_2 in names_2:
+#         if name_1 == name_2:
+#             duplicates.append(name_1)
+
+#Using BST to cut runtime
+
+head = names_1[0]
+names_1 = names_1[1:]
+
+bst = BSTNode(head)
+
+for name in names_1:
+    bst.insert(name)
+
+for name in names_2:
+    if bst.contains(name):
+        duplicates.append(name)
+
+# RUNTIME : 0.16530179977416992 seconds , 64 Duplicates
 
 end_time = time.time()
 print (f"{len(duplicates)} duplicates:\n\n{', '.join(duplicates)}\n\n")

From fb36ef36fcdc586f2d73086e82d24830acce11af Mon Sep 17 00:00:00 2001
From: kmk028 <kmk028@users.noreply.github.com>
Date: Sun, 27 Sep 2020 19:28:06 -0700
Subject: [PATCH 3/3] reverse Linked list and Stretch goal completed

---
 names/names.py     | 25 +++++++++++++++++++++++++
 reverse/reverse.py | 15 ++++++++++++++-
 2 files changed, 39 insertions(+), 1 deletion(-)

diff --git a/names/names.py b/names/names.py
index a806ba07e..502a7d934 100644
--- a/names/names.py
+++ b/names/names.py
@@ -42,3 +42,28 @@
 # Python has built-in tools that allow for a very efficient approach to this problem
 # What's the best time you can accomplish?  Thare are no restrictions on techniques or data
 # structures, but you may not import any additional libraries that you did not write yourself.
+
+start_time = time.time()
+
+f = open('names_1.txt', 'r')
+names_3 = f.read().split("\n")  # List containing 10000 names
+f.close()
+
+f = open('names_2.txt', 'r')
+names_4 = f.read().split("\n")  # List containing 10000 names
+f.close()
+
+duplicates1 = []  # Return the list of duplicates in this data structure
+
+def intersection(lst1, lst2): 
+    temp = set(lst2) 
+    lst3 = [value for value in lst1 if value in temp] 
+    return lst3
+
+duplicates1 = intersection(names_3,names_4)
+
+end_time = time.time()
+print (f"{len(duplicates1)} duplicates:\n\n{', '.join(duplicates1)}\n\n")
+print (f"runtime: {end_time - start_time} seconds")
+
+##Runtime reduced to 0.003970146179199219 seconds
diff --git a/reverse/reverse.py b/reverse/reverse.py
index 6116252d1..21273d259 100644
--- a/reverse/reverse.py
+++ b/reverse/reverse.py
@@ -39,4 +39,17 @@ def contains(self, value):
         return False
 
     def reverse_list(self, node, prev):
-        pass
+        # Iterative solution
+        # initialize 3 pointers. Prev = Null, curr = head, next is null 
+        prev = None
+        current = self.head 
+        # store the next node before changeing it
+        # change the next pointer to previous. this is where it does reverse
+        # move prev and current 1 step ahead
+        # repeat process till current node is not null. 
+        while current:
+            next = current.next_node
+            current.next_node = prev
+            prev=current
+            current=next
+        self.head=prev