From 455be01dfd04d601cc6d13bbec3d48003b54c283 Mon Sep 17 00:00:00 2001
From: Abhishek2019 <abhishekw13@gmail.com>
Date: Tue, 6 Feb 2018 22:51:29 +0530
Subject: [PATCH 01/20] Dynamic Programming: Coint-Change-Problem

---
 README.md                                     |  4 +--
 .../Coin-Change-Problem/solution.py           | 28 +++++++++++++++++++
 2 files changed, 30 insertions(+), 2 deletions(-)
 create mode 100644 solution/practice/algorithms/dynamic-programming/Coin-Change-Problem/solution.py

diff --git a/README.md b/README.md
index acd8b55..732c788 100644
--- a/README.md
+++ b/README.md
@@ -22,7 +22,7 @@ Algorithms
 * [Search](#search) (3/23)
 * [Graph Theory](#graph-theory) (2/58)
 * [Greedy](#greedy) (8/22)
-* [Dynamic Programming](#dynamic-programming) (8/94)
+* [Dynamic Programming](#dynamic-programming) (9/94)
 * [Constructive Algorithms](#constructive-algorithms) (2/11)
 * [Bit Manipulation](#bit-manipulation) (0/25)
 * [Recursion](#recursion) (3/10)
@@ -294,7 +294,7 @@ Algorithms
 ### Dynamic Programming
 \# | Challenge | Solution
 :---:|:---:|:---:
-1 | [The Coin Change Problem](https://www.hackerrank.com/challenges/coin-change) | WIP
+1 | [The Coin Change Problem](https://www.hackerrank.com/challenges/coin-change) | [Solution & Comment](solution/practice/algorithms/dynamic-programming/Coin-Change-Problem/solution.py)
 2 | [Equal](https://www.hackerrank.com/challenges/equal) | WIP
 3 | [Sherlock and Cost](https://www.hackerrank.com/challenges/sherlock-and-cost) | [Solution & Comment](solution/practice/algorithms/dynamic-programming/sherlock-and-cost/solution.py)
 4 | [Kingdom Division](https://www.hackerrank.com/challenges/kingdom-division) | WIP
diff --git a/solution/practice/algorithms/dynamic-programming/Coin-Change-Problem/solution.py b/solution/practice/algorithms/dynamic-programming/Coin-Change-Problem/solution.py
new file mode 100644
index 0000000..fe9861e
--- /dev/null
+++ b/solution/practice/algorithms/dynamic-programming/Coin-Change-Problem/solution.py
@@ -0,0 +1,28 @@
+#!/bin/python3
+
+import sys
+
+def getWays(n, c):
+    workArea = [0 for i in range(n+1)]
+    workArea[0] = 1
+    countCoin = 0
+    
+    
+    while(countCoin < len(c)):
+        
+        for i in range(1,n+1):
+            
+            if(c[countCoin]<=i):
+                workArea[i] = workArea[i]+workArea[i-c[countCoin]]
+        countCoin += 1
+   
+    return(workArea[-1])            
+                
+    
+    
+n, m = input().strip().split(' ')
+n, m = [int(n), int(m)]
+c = list(map(int, input().strip().split(' ')))
+# Print the number of ways of making change for 'n' units using coins having the values given by 'c'
+ways = getWays(n, c)
+print(ways)

From 5f6531162f40d95a07de15eb9dbcbde0bf897038 Mon Sep 17 00:00:00 2001
From: Abhishek2019 <abhishekw13@gmail.com>
Date: Tue, 6 Feb 2018 22:59:01 +0530
Subject: [PATCH 02/20] README.md file modified

---
 README.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/README.md b/README.md
index 732c788..9f4ab1b 100644
--- a/README.md
+++ b/README.md
@@ -8,7 +8,7 @@ The index below is auto-generated. See [update-challenge-list.py](util/update-ch
 Index
 ======
 
-* [Algorithms](#algorithms) (60/409)
+* [Algorithms](#algorithms) (61/409)
 * [Data Structures](#data-structures) (11/114)
 * [Mathematics](#mathematics) (1/250)
 

From 4bb49cf1b7f818cedcf4f9ee0145b4a14dec3ad4 Mon Sep 17 00:00:00 2001
From: satyam857 <satyamrsingh857@gmail.com>
Date: Mon, 22 Oct 2018 17:34:23 +0530
Subject: [PATCH 03/20] Angry Professor Solution Added

---
 README.md                                           |  4 ++--
 .../implementation/AngryProfessor/solution.py       | 13 +++++++++++++
 2 files changed, 15 insertions(+), 2 deletions(-)
 create mode 100644 solution/practice/algorithms/implementation/AngryProfessor/solution.py

diff --git a/README.md b/README.md
index 9f4ab1b..602f0e7 100644
--- a/README.md
+++ b/README.md
@@ -16,7 +16,7 @@ Algorithms
 ------
 
 * [Warmup](#warmup) (9/9)
-* [Implementation](#implementation) (8/59)
+* [Implementation](#implementation) (9/59)
 * [Strings](#strings) (11/45)
 * [Sorting](#sorting) (5/18)
 * [Search](#search) (3/23)
@@ -61,7 +61,7 @@ Algorithms
 14 | [The Hurdle Race](https://www.hackerrank.com/challenges/the-hurdle-race) | WIP
 15 | [Designer PDF Viewer](https://www.hackerrank.com/challenges/designer-pdf-viewer) | WIP
 16 | [Utopian Tree](https://www.hackerrank.com/challenges/utopian-tree) | WIP
-17 | [Angry Professor](https://www.hackerrank.com/challenges/angry-professor) | WIP
+17 | [Angry Professor](https://www.hackerrank.com/challenges/angry-professor) | [Solution & Comment](solution/practice/algorithms/implementation/AngryProfessor/solution.py)
 18 | [Beautiful Days at the Movies](https://www.hackerrank.com/challenges/beautiful-days-at-the-movies) | WIP
 19 | [Viral Advertising](https://www.hackerrank.com/challenges/strange-advertising) | WIP
 20 | [Save the Prisoner!](https://www.hackerrank.com/challenges/save-the-prisoner) | WIP
diff --git a/solution/practice/algorithms/implementation/AngryProfessor/solution.py b/solution/practice/algorithms/implementation/AngryProfessor/solution.py
new file mode 100644
index 0000000..efb9a70
--- /dev/null
+++ b/solution/practice/algorithms/implementation/AngryProfessor/solution.py
@@ -0,0 +1,13 @@
+testcase = int(input())
+for i in range(testcase):
+    n , k = list(map(int,input().split(" ")))
+    count = 0
+    s = list(map(int,input().split(" ")))
+    for j in s:
+        if(j <= 0):
+            count +=1
+    if(count >= k):
+        print("NO")
+    else:
+        print("YES")
+

From 2edd5aa8aa4994561d7b94bebe0ddceb49f75033 Mon Sep 17 00:00:00 2001
From: satyam857 <satyamrsingh857@gmail.com>
Date: Mon, 22 Oct 2018 17:43:52 +0530
Subject: [PATCH 04/20] The Hurdle Race Solution is Added

---
 README.md                                       |  4 ++--
 .../implementation/TheHurdleRace/solution.py    | 17 +++++++++++++++++
 2 files changed, 19 insertions(+), 2 deletions(-)
 create mode 100644 solution/practice/algorithms/implementation/TheHurdleRace/solution.py

diff --git a/README.md b/README.md
index 602f0e7..7da5692 100644
--- a/README.md
+++ b/README.md
@@ -16,7 +16,7 @@ Algorithms
 ------
 
 * [Warmup](#warmup) (9/9)
-* [Implementation](#implementation) (9/59)
+* [Implementation](#implementation) (10/59)
 * [Strings](#strings) (11/45)
 * [Sorting](#sorting) (5/18)
 * [Search](#search) (3/23)
@@ -58,7 +58,7 @@ Algorithms
 11 | [Cats and a Mouse](https://www.hackerrank.com/challenges/cats-and-a-mouse) | WIP
 12 | [Picking Numbers](https://www.hackerrank.com/challenges/picking-numbers) | WIP
 13 | [Climbing the Leaderboard](https://www.hackerrank.com/challenges/climbing-the-leaderboard) | WIP
-14 | [The Hurdle Race](https://www.hackerrank.com/challenges/the-hurdle-race) | WIP
+14 | [The Hurdle Race](https://www.hackerrank.com/challenges/the-hurdle-race) | [Solution & Comment](solution/practice/algorithms/implementation/TheHurdleRace/solution.py)
 15 | [Designer PDF Viewer](https://www.hackerrank.com/challenges/designer-pdf-viewer) | WIP
 16 | [Utopian Tree](https://www.hackerrank.com/challenges/utopian-tree) | WIP
 17 | [Angry Professor](https://www.hackerrank.com/challenges/angry-professor) | [Solution & Comment](solution/practice/algorithms/implementation/AngryProfessor/solution.py)
diff --git a/solution/practice/algorithms/implementation/TheHurdleRace/solution.py b/solution/practice/algorithms/implementation/TheHurdleRace/solution.py
new file mode 100644
index 0000000..f0a73e6
--- /dev/null
+++ b/solution/practice/algorithms/implementation/TheHurdleRace/solution.py
@@ -0,0 +1,17 @@
+#!/bin/python3
+
+import sys
+
+def hurdleRace(k, height):
+    temp = max(height)-k 
+    if (temp > 0):
+        return temp
+    else:
+        return 0
+    
+if __name__ == "__main__":
+    n, k = input().strip().split(' ')
+    n, k = [int(n), int(k)]
+    height = list(map(int, input().strip().split(' ')))
+    result = hurdleRace(k, height)
+    print(result)

From 26f50d513f01c4902994b1c743780a450686542c Mon Sep 17 00:00:00 2001
From: satyam857 <satyamrsingh857@gmail.com>
Date: Mon, 22 Oct 2018 18:12:48 +0530
Subject: [PATCH 05/20] The Maximum Subarray Solution is Added

---
 README.md                                     |  4 +-
 .../TheMaximumSubarray/solution.py            | 46 +++++++++++++++++++
 2 files changed, 48 insertions(+), 2 deletions(-)
 create mode 100644 solution/practice/algorithms/dynamic-programming/TheMaximumSubarray/solution.py

diff --git a/README.md b/README.md
index 7da5692..c19830e 100644
--- a/README.md
+++ b/README.md
@@ -22,7 +22,7 @@ Algorithms
 * [Search](#search) (3/23)
 * [Graph Theory](#graph-theory) (2/58)
 * [Greedy](#greedy) (8/22)
-* [Dynamic Programming](#dynamic-programming) (9/94)
+* [Dynamic Programming](#dynamic-programming) (10/94)
 * [Constructive Algorithms](#constructive-algorithms) (2/11)
 * [Bit Manipulation](#bit-manipulation) (0/25)
 * [Recursion](#recursion) (3/10)
@@ -305,7 +305,7 @@ Algorithms
 9 | [Abbreviation](https://www.hackerrank.com/challenges/abbr) | [Solution & Comment](solution/practice/algorithms/dynamic-programming/abbr/solution.py)
 10 | [Decibinary Numbers](https://www.hackerrank.com/challenges/decibinary-numbers) | WIP
 11 | [Fair Cut](https://www.hackerrank.com/challenges/fair-cut) | WIP
-12 | [The Maximum Subarray](https://www.hackerrank.com/challenges/maxsubarray) | WIP
+12 | [The Maximum Subarray](https://www.hackerrank.com/challenges/maxsubarray) | [Solution & Comment](solution/practice/algorithms/dynamic-programming/TheMaximumSubarray/solution.py)
 13 | [Angry Children 2](https://www.hackerrank.com/challenges/angry-children-2) | WIP
 14 | [Sherlock's Array Merging Algorithm](https://www.hackerrank.com/challenges/sherlocks-array-merging-algorithm) | WIP
 15 | [Prime Digit Sums](https://www.hackerrank.com/challenges/prime-digit-sums) | WIP
diff --git a/solution/practice/algorithms/dynamic-programming/TheMaximumSubarray/solution.py b/solution/practice/algorithms/dynamic-programming/TheMaximumSubarray/solution.py
new file mode 100644
index 0000000..5295908
--- /dev/null
+++ b/solution/practice/algorithms/dynamic-programming/TheMaximumSubarray/solution.py
@@ -0,0 +1,46 @@
+#!/bin/python3
+
+import math
+import os
+import random
+import re
+import sys
+
+# Complete the maxSubarray function below.
+def maxSubarray(arr):
+    sub_array_sum = -sys.maxsize
+    sub_sequ_sum = arr[0]
+    current_sum=0    
+    
+    for i in arr:
+        current_sum += i
+        if sub_array_sum < current_sum:
+            sub_array_sum = current_sum
+        if current_sum < 0:
+            current_sum=0
+    for i in range(1, len(arr)):
+        if arr[i] > 0 and sub_sequ_sum >= 0 :
+            sub_sequ_sum += arr[i]
+        elif sub_sequ_sum < 0 and sub_sequ_sum < arr[i]:
+            sub_sequ_sum = arr[i]
+    return [sub_array_sum,sub_sequ_sum]
+
+    
+    
+    
+if __name__ == '__main__':
+    fptr = open(os.environ['OUTPUT_PATH'], 'w')
+
+    t = int(input())
+
+    for t_itr in range(t):
+        n = int(input())
+
+        arr = list(map(int, input().rstrip().split()))
+
+        result = maxSubarray(arr)
+
+        fptr.write(' '.join(map(str, result)))
+        fptr.write('\n')
+
+    fptr.close()

From b4e114f6b4055b75fc7a85f5b6cf024e93c78b3e Mon Sep 17 00:00:00 2001
From: satyam857 <satyamrsingh857@gmail.com>
Date: Mon, 22 Oct 2018 18:35:13 +0530
Subject: [PATCH 06/20] Linked List Print the Element problem solved

---
 README.md                                       |  4 ++--
 .../solution.py                                 | 17 +++++++++++++++++
 2 files changed, 19 insertions(+), 2 deletions(-)
 create mode 100644 solution/practice/data-structures/linked-list/print-the-elements-of-a-linked-list/solution.py

diff --git a/README.md b/README.md
index c19830e..5787319 100644
--- a/README.md
+++ b/README.md
@@ -494,7 +494,7 @@ Data Structures
 ------
 
 * [Arrays](#arrays) (6/6)
-* [Linked Lists](#linked-lists) (0/15)
+* [Linked Lists](#linked-lists) (1/15)
 * [Trees](#trees) (0/15)
 * [Balanced Trees](#balanced-trees) (0/3)
 * [Stacks](#stacks) (0/9)
@@ -518,7 +518,7 @@ Data Structures
 ### Linked Lists
 \# | Challenge | Solution
 :---:|:---:|:---:
-1 | [Print the Elements of a Linked List](https://www.hackerrank.com/challenges/print-the-elements-of-a-linked-list) | WIP
+1 | [Print the Elements of a Linked List](https://www.hackerrank.com/challenges/print-the-elements-of-a-linked-list) | [Solution & Comment](solution/practice/data-structures/linked-list/print-the-elements-of-a-linked-list/solution.py)
 2 | [Insert a Node at the Tail of a Linked List](https://www.hackerrank.com/challenges/insert-a-node-at-the-tail-of-a-linked-list) | WIP
 3 | [Insert a node at the head of a linked list](https://www.hackerrank.com/challenges/insert-a-node-at-the-head-of-a-linked-list) | WIP
 4 | [Insert a node at a specific position in a linked list](https://www.hackerrank.com/challenges/insert-a-node-at-a-specific-position-in-a-linked-list) | WIP
diff --git a/solution/practice/data-structures/linked-list/print-the-elements-of-a-linked-list/solution.py b/solution/practice/data-structures/linked-list/print-the-elements-of-a-linked-list/solution.py
new file mode 100644
index 0000000..0d5d476
--- /dev/null
+++ b/solution/practice/data-structures/linked-list/print-the-elements-of-a-linked-list/solution.py
@@ -0,0 +1,17 @@
+# Complete the printLinkedList function below.
+
+#
+# For your reference:
+#
+# SinglyLinkedListNode:
+#     int data
+#     SinglyLinkedListNode next
+#
+#
+def printLinkedList(head):
+    if head == None:
+        return;
+    n = head
+    while(n != None):
+        print(n.data)
+        n = n.next
\ No newline at end of file

From c244f81e29a00ee991628ea524297ad4ed773312 Mon Sep 17 00:00:00 2001
From: satyam857 <satyamrsingh857@gmail.com>
Date: Mon, 22 Oct 2018 19:00:57 +0530
Subject: [PATCH 07/20] Solution of Tree Preorder traversal

---
 README.md                                            |  4 ++--
 .../trees/TreePreorderTraversal/solution.py          | 12 ++++++++++++
 2 files changed, 14 insertions(+), 2 deletions(-)
 create mode 100644 solution/practice/data-structures/trees/TreePreorderTraversal/solution.py

diff --git a/README.md b/README.md
index 5787319..4f48599 100644
--- a/README.md
+++ b/README.md
@@ -495,7 +495,7 @@ Data Structures
 
 * [Arrays](#arrays) (6/6)
 * [Linked Lists](#linked-lists) (1/15)
-* [Trees](#trees) (0/15)
+* [Trees](#trees) (1/15)
 * [Balanced Trees](#balanced-trees) (0/3)
 * [Stacks](#stacks) (0/9)
 * [Queues](#queues) (0/5)
@@ -537,7 +537,7 @@ Data Structures
 ### Trees
 \# | Challenge | Solution
 :---:|:---:|:---:
-1 | [Tree: Preorder Traversal](https://www.hackerrank.com/challenges/tree-preorder-traversal) | WIP
+1 | [Tree: Preorder Traversal](https://www.hackerrank.com/challenges/tree-preorder-traversal) | [Solution & Comment](solution/practice/data-structures/trees/TreePreorderTraversal/solution.py)
 2 | [Tree: Postorder Traversal](https://www.hackerrank.com/challenges/tree-postorder-traversal) | WIP
 3 | [Tree: Inorder Traversal](https://www.hackerrank.com/challenges/tree-inorder-traversal) | WIP
 4 | [Tree: Height of a Binary Tree](https://www.hackerrank.com/challenges/tree-height-of-a-binary-tree) | WIP
diff --git a/solution/practice/data-structures/trees/TreePreorderTraversal/solution.py b/solution/practice/data-structures/trees/TreePreorderTraversal/solution.py
new file mode 100644
index 0000000..bf6e856
--- /dev/null
+++ b/solution/practice/data-structures/trees/TreePreorderTraversal/solution.py
@@ -0,0 +1,12 @@
+"""
+Node is defined as
+self.left (the left child of the node)
+self.right (the right child of the node)
+self.info (the value of the node)
+"""
+def preOrder(root):
+    if root != None :
+        print(root.info,end=" ")
+        preOrder(root.left)
+        preOrder(root.right)
+    return
\ No newline at end of file

From a9e472aaab7d548392ae33d15530c23ee822a509 Mon Sep 17 00:00:00 2001
From: root <root@localhost.localdomain>
Date: Tue, 23 Oct 2018 05:57:41 +0000
Subject: [PATCH 08/20] Tree Inorder Traversal Solution is Added

---
 README.md                                            |  4 ++--
 .../trees/TreeInorderTraversal/solution.py           | 12 ++++++++++++
 2 files changed, 14 insertions(+), 2 deletions(-)
 create mode 100644 solution/practice/data-structures/trees/TreeInorderTraversal/solution.py

diff --git a/README.md b/README.md
index 4f48599..c6b17d1 100644
--- a/README.md
+++ b/README.md
@@ -495,7 +495,7 @@ Data Structures
 
 * [Arrays](#arrays) (6/6)
 * [Linked Lists](#linked-lists) (1/15)
-* [Trees](#trees) (1/15)
+* [Trees](#trees) (2/15)
 * [Balanced Trees](#balanced-trees) (0/3)
 * [Stacks](#stacks) (0/9)
 * [Queues](#queues) (0/5)
@@ -539,7 +539,7 @@ Data Structures
 :---:|:---:|:---:
 1 | [Tree: Preorder Traversal](https://www.hackerrank.com/challenges/tree-preorder-traversal) | [Solution & Comment](solution/practice/data-structures/trees/TreePreorderTraversal/solution.py)
 2 | [Tree: Postorder Traversal](https://www.hackerrank.com/challenges/tree-postorder-traversal) | WIP
-3 | [Tree: Inorder Traversal](https://www.hackerrank.com/challenges/tree-inorder-traversal) | WIP
+3 | [Tree: Inorder Traversal](https://www.hackerrank.com/challenges/tree-inorder-traversal) | [Solution & Comment](solution/practice/data-structures/trees/TreeInorderTraversal/solution.py)
 4 | [Tree: Height of a Binary Tree](https://www.hackerrank.com/challenges/tree-height-of-a-binary-tree) | WIP
 5 | [Tree : Top View](https://www.hackerrank.com/challenges/tree-top-view) | WIP
 6 | [Tree: Level Order Traversal](https://www.hackerrank.com/challenges/tree-level-order-traversal) | WIP
diff --git a/solution/practice/data-structures/trees/TreeInorderTraversal/solution.py b/solution/practice/data-structures/trees/TreeInorderTraversal/solution.py
new file mode 100644
index 0000000..2697ee1
--- /dev/null
+++ b/solution/practice/data-structures/trees/TreeInorderTraversal/solution.py
@@ -0,0 +1,12 @@
+"""
+Node is defined as
+self.left (the left child of the node)
+self.right (the right child of the node)
+self.info (the value of the node)
+"""
+def inOrder(root):
+    if root != None :
+        inOrder(root.left)
+        print(root.info,end=" ")
+        inOrder(root.right)
+    
\ No newline at end of file

From 312a15a2786df757abc1184c3b3ab3ca6f0c6062 Mon Sep 17 00:00:00 2001
From: Vikas Vishwakarma <vikas.vishwakarma01@gmail.com>
Date: Tue, 30 Oct 2018 21:40:01 +0530
Subject: [PATCH 09/20] Added Sherlock and squares in inplementation

---
 .../Sherlock And Squares/solution.py              | 15 +++++++++++++++
 1 file changed, 15 insertions(+)
 create mode 100644 solution/practice/algorithms/implementation/Sherlock And Squares/solution.py

diff --git a/solution/practice/algorithms/implementation/Sherlock And Squares/solution.py b/solution/practice/algorithms/implementation/Sherlock And Squares/solution.py
new file mode 100644
index 0000000..750f47d
--- /dev/null
+++ b/solution/practice/algorithms/implementation/Sherlock And Squares/solution.py	
@@ -0,0 +1,15 @@
+import math
+
+
+def squares(a, b):
+    return math.floor(math.sqrt(b)) - math.ceil(math.sqrt(a)) + 1
+
+
+if __name__ == '__main__':
+    q = int(input())
+    for q_itr in range(q):
+        ab = input().split()
+        a = int(ab[0])
+        b = int(ab[1])
+        result = squares(a, b)
+        print(result)

From 221dde7a22f2247e96ac0e389c585cad0fee668b Mon Sep 17 00:00:00 2001
From: Vikas Vishwakarma <vikas.vishwakarma01@gmail.com>
Date: Tue, 30 Oct 2018 21:56:18 +0530
Subject: [PATCH 10/20] Adder Designer Pdf Viewer in implementation

---
 .../implementation/Designer PDF Viewer/solution.py     | 10 ++++++++++
 1 file changed, 10 insertions(+)
 create mode 100644 solution/practice/algorithms/implementation/Designer PDF Viewer/solution.py

diff --git a/solution/practice/algorithms/implementation/Designer PDF Viewer/solution.py b/solution/practice/algorithms/implementation/Designer PDF Viewer/solution.py
new file mode 100644
index 0000000..f138fb2
--- /dev/null
+++ b/solution/practice/algorithms/implementation/Designer PDF Viewer/solution.py	
@@ -0,0 +1,10 @@
+def designerPdfViewer(h, word):
+    word_height = [h[ord(c)-ord("a")] for c in word ]
+    return max(word_height)*len(word)
+
+
+if __name__ == '__main__':
+    h = list(map(int, input().rstrip().split()))
+    word = input()
+    result = designerPdfViewer(h, word)
+    print(result)

From 754a083996223462c714090b6595a8cded175cbf Mon Sep 17 00:00:00 2001
From: Vikas Vishwakarma <vikas.vishwakarma01@gmail.com>
Date: Tue, 30 Oct 2018 22:18:12 +0530
Subject: [PATCH 11/20] Added Cats and mouse in implementation

---
 .../implementation/Cats and a mouse/solution.py  | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)
 create mode 100644 solution/practice/algorithms/implementation/Cats and a mouse/solution.py

diff --git a/solution/practice/algorithms/implementation/Cats and a mouse/solution.py b/solution/practice/algorithms/implementation/Cats and a mouse/solution.py
new file mode 100644
index 0000000..6d302b4
--- /dev/null
+++ b/solution/practice/algorithms/implementation/Cats and a mouse/solution.py	
@@ -0,0 +1,16 @@
+def catAndMouse(ca, cb, m):
+    if abs(m - ca) == abs(m - cb):
+        return "Mouse C"
+    else:
+        return "Cat A" if abs(m - ca) < abs(m - cb) else "Cat B"
+
+if __name__ == '__main__':
+    q = int(input())
+    for q_itr in range(q):
+        xyz = input().split()
+        x = int(xyz[0])
+        y = int(xyz[1])
+        z = int(xyz[2])
+        result = catAndMouse(x, y, z)
+
+        print(result)
\ No newline at end of file

From cec7fbfd7a1104964c8061db1c046315a5dcd18e Mon Sep 17 00:00:00 2001
From: Vikas Vishwakarma <vikas.vishwakarma01@gmail.com>
Date: Tue, 30 Oct 2018 22:27:36 +0530
Subject: [PATCH 12/20] Added Utopian tree in implementation

---
 .../implementation/Utopian Tree/solution.py      | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)
 create mode 100644 solution/practice/algorithms/implementation/Utopian Tree/solution.py

diff --git a/solution/practice/algorithms/implementation/Utopian Tree/solution.py b/solution/practice/algorithms/implementation/Utopian Tree/solution.py
new file mode 100644
index 0000000..92e0e2e
--- /dev/null
+++ b/solution/practice/algorithms/implementation/Utopian Tree/solution.py	
@@ -0,0 +1,16 @@
+def utopianTree(n):
+    height = 1
+    for i in range(n):
+        if i % 2 == 0:
+            height *= 2
+        else:
+            height += 1
+    return height
+
+
+if __name__ == '__main__':
+    t = int(input())
+    for t_itr in range(t):
+        n = int(input())
+        result = utopianTree(n)
+        print(result)
\ No newline at end of file

From aa84612c83e8c04b7afcc2eff748fc327892f7e8 Mon Sep 17 00:00:00 2001
From: Vikas Vishwakarma <vikas.vishwakarma01@gmail.com>
Date: Tue, 30 Oct 2018 22:47:06 +0530
Subject: [PATCH 13/20] Added Append and delete in implementation and updated
 the readme file

---
 README.md                                       | 10 +++++-----
 .../Append-and-Delete/solution.py               | 17 +++++++++++++++++
 .../solution.py                                 |  0
 .../solution.py                                 |  0
 .../solution.py                                 |  0
 .../{Utopian Tree => Utopian-Tree}/solution.py  |  0
 6 files changed, 22 insertions(+), 5 deletions(-)
 create mode 100644 solution/practice/algorithms/implementation/Append-and-Delete/solution.py
 rename solution/practice/algorithms/implementation/{Cats and a mouse => Cats-and-a-mouse}/solution.py (100%)
 rename solution/practice/algorithms/implementation/{Designer PDF Viewer => Designer-PDF-Viewer}/solution.py (100%)
 rename solution/practice/algorithms/implementation/{Sherlock And Squares => Sherlock-And-Squares}/solution.py (100%)
 rename solution/practice/algorithms/implementation/{Utopian Tree => Utopian-Tree}/solution.py (100%)

diff --git a/README.md b/README.md
index c6b17d1..23ee39f 100644
--- a/README.md
+++ b/README.md
@@ -55,12 +55,12 @@ Algorithms
 8 | [Bon App¨¦tit](https://www.hackerrank.com/challenges/bon-appetit) | [Solution & Comment](solution/practice/algorithms/implementation/bon-appetit/solution.py)
 9 | [Sock Merchant](https://www.hackerrank.com/challenges/sock-merchant) | [Solution & Comment](solution/practice/algorithms/implementation/sock-merchant/solution.py)
 10 | [Drawing Book ](https://www.hackerrank.com/challenges/drawing-book) | WIP
-11 | [Cats and a Mouse](https://www.hackerrank.com/challenges/cats-and-a-mouse) | WIP
+11 | [Cats and a Mouse](https://www.hackerrank.com/challenges/cats-and-a-mouse) | [Solution & Comment](solution/practice/algorithms/implementation/Cats-and-a-mouse/solution.py) 
 12 | [Picking Numbers](https://www.hackerrank.com/challenges/picking-numbers) | WIP
 13 | [Climbing the Leaderboard](https://www.hackerrank.com/challenges/climbing-the-leaderboard) | WIP
 14 | [The Hurdle Race](https://www.hackerrank.com/challenges/the-hurdle-race) | [Solution & Comment](solution/practice/algorithms/implementation/TheHurdleRace/solution.py)
-15 | [Designer PDF Viewer](https://www.hackerrank.com/challenges/designer-pdf-viewer) | WIP
-16 | [Utopian Tree](https://www.hackerrank.com/challenges/utopian-tree) | WIP
+15 | [Designer PDF Viewer](https://www.hackerrank.com/challenges/designer-pdf-viewer) | [Solution & Comment](solution/practice/algorithms/implementation/Designer-PDF-Viewer/solution.py)
+16 | [Utopian Tree](https://www.hackerrank.com/challenges/utopian-tree) | [Solution & Comment](solution/practice/algorithms/implementation/Utopian-Tree/solution.py)
 17 | [Angry Professor](https://www.hackerrank.com/challenges/angry-professor) | [Solution & Comment](solution/practice/algorithms/implementation/AngryProfessor/solution.py)
 18 | [Beautiful Days at the Movies](https://www.hackerrank.com/challenges/beautiful-days-at-the-movies) | WIP
 19 | [Viral Advertising](https://www.hackerrank.com/challenges/strange-advertising) | WIP
@@ -70,8 +70,8 @@ Algorithms
 23 | [Jumping on the Clouds: Revisited](https://www.hackerrank.com/challenges/jumping-on-the-clouds-revisited) | WIP
 24 | [Find Digits](https://www.hackerrank.com/challenges/find-digits) | WIP
 25 | [Extra Long Factorials](https://www.hackerrank.com/challenges/extra-long-factorials) | WIP
-26 | [Append and Delete](https://www.hackerrank.com/challenges/append-and-delete) | WIP
-27 | [Sherlock and Squares](https://www.hackerrank.com/challenges/sherlock-and-squares) | WIP
+26 | [Append and Delete](https://www.hackerrank.com/challenges/append-and-delete) | [Solution & Comment](solution/practice/algorithms/implementation/Append-and-Delete/solution.py)
+27 | [Sherlock and Squares](https://www.hackerrank.com/challenges/sherlock-and-squares) | [Solution & Comment](solution/practice/algorithms/implementation/Sherlock-And-Squares/solution.py)
 28 | [Library Fine](https://www.hackerrank.com/challenges/library-fine) | WIP
 29 | [Cut the sticks](https://www.hackerrank.com/challenges/cut-the-sticks) | WIP
 30 | [Non-Divisible Subset](https://www.hackerrank.com/challenges/non-divisible-subset) | WIP
diff --git a/solution/practice/algorithms/implementation/Append-and-Delete/solution.py b/solution/practice/algorithms/implementation/Append-and-Delete/solution.py
new file mode 100644
index 0000000..dda0412
--- /dev/null
+++ b/solution/practice/algorithms/implementation/Append-and-Delete/solution.py
@@ -0,0 +1,17 @@
+def appendAndDelete(s, t, k):
+    numSameChars = min(len(s), len(t))
+    for i in range(len(t)):
+        if s[:i] != t[:i]:
+            numSameChars = i - 1
+            break
+
+    diff = len(s) - numSameChars + len(t) - numSameChars
+    return 'Yes' if (diff <= k and diff % 2 == k % 2) or len(s) + len(t) < k else 'No'
+
+
+if __name__ == '__main__':
+    s = input()
+    t = input()
+    k = int(input())
+    result = appendAndDelete(s, t, k)
+    print(result)
\ No newline at end of file
diff --git a/solution/practice/algorithms/implementation/Cats and a mouse/solution.py b/solution/practice/algorithms/implementation/Cats-and-a-mouse/solution.py
similarity index 100%
rename from solution/practice/algorithms/implementation/Cats and a mouse/solution.py
rename to solution/practice/algorithms/implementation/Cats-and-a-mouse/solution.py
diff --git a/solution/practice/algorithms/implementation/Designer PDF Viewer/solution.py b/solution/practice/algorithms/implementation/Designer-PDF-Viewer/solution.py
similarity index 100%
rename from solution/practice/algorithms/implementation/Designer PDF Viewer/solution.py
rename to solution/practice/algorithms/implementation/Designer-PDF-Viewer/solution.py
diff --git a/solution/practice/algorithms/implementation/Sherlock And Squares/solution.py b/solution/practice/algorithms/implementation/Sherlock-And-Squares/solution.py
similarity index 100%
rename from solution/practice/algorithms/implementation/Sherlock And Squares/solution.py
rename to solution/practice/algorithms/implementation/Sherlock-And-Squares/solution.py
diff --git a/solution/practice/algorithms/implementation/Utopian Tree/solution.py b/solution/practice/algorithms/implementation/Utopian-Tree/solution.py
similarity index 100%
rename from solution/practice/algorithms/implementation/Utopian Tree/solution.py
rename to solution/practice/algorithms/implementation/Utopian-Tree/solution.py

From 6e82644da04e2a948008a7896ee07c6f8dc22f92 Mon Sep 17 00:00:00 2001
From: root <root@localhost.localdomain>
Date: Mon, 28 Oct 2019 15:46:46 +0000
Subject: [PATCH 14/20] MCQ1 Answer is added

---
 .../kindergarten-adventures/solution.py       | 22 +++++++++++++++++++
 .../how-well-do-you-know-trees/solution.py    |  1 +
 2 files changed, 23 insertions(+)
 create mode 100644 solution/practice/data-structures/advanced/kindergarten-adventures/solution.py
 create mode 100644 solution/practice/data-structures/multiple-choice/how-well-do-you-know-trees/solution.py

diff --git a/solution/practice/data-structures/advanced/kindergarten-adventures/solution.py b/solution/practice/data-structures/advanced/kindergarten-adventures/solution.py
new file mode 100644
index 0000000..adbf3e1
--- /dev/null
+++ b/solution/practice/data-structures/advanced/kindergarten-adventures/solution.py
@@ -0,0 +1,22 @@
+# For student i, we can find two (possibly empty) ranges
+# of time when they are available:
+# * [0, i - t_i]
+# * the first one wrapped around 0, which is (i, i - t_i + n]
+#
+# To get the available student number, we then have to add
+# one to the counting array for each minute mark in these intervals.
+# This can be done in O(n) time using the awesome algorithm
+# described at http://stackoverflow.com/a/18410273.
+
+n = int(input())
+A = [0] * (n + 1)
+for i, x in enumerate(map(int, input().split())):
+  r1 = max(-1, i - x) + 1
+  r2 = min(max(i, i - x + n) + 1, n)
+  A[0] +=  1
+  A[r1] -= 1
+  A[i + 1] += 1
+  A[r2] -= 1
+for i in range(n):
+  A[i + 1] += A[i]
+print(A.index(max(A)) + 1)
diff --git a/solution/practice/data-structures/multiple-choice/how-well-do-you-know-trees/solution.py b/solution/practice/data-structures/multiple-choice/how-well-do-you-know-trees/solution.py
new file mode 100644
index 0000000..fc9723e
--- /dev/null
+++ b/solution/practice/data-structures/multiple-choice/how-well-do-you-know-trees/solution.py
@@ -0,0 +1 @@
+print("n-1")

From 7121b665c5feba37854ada1f8e8c3a94aeb0594d Mon Sep 17 00:00:00 2001
From: root <root@localhost.localdomain>
Date: Mon, 28 Oct 2019 15:54:32 +0000
Subject: [PATCH 15/20] MCQ solution location updated in Readme.md file

---
 README.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/README.md b/README.md
index c6b17d1..3ebe292 100644
--- a/README.md
+++ b/README.md
@@ -601,7 +601,7 @@ Data Structures
 ### Multiple Choice
 \# | Challenge | Solution
 :---:|:---:|:---:
-1 | [ Data Structures MCQ 1](https://www.hackerrank.com/challenges/how-well-do-you-know-trees) | WIP
+1 | [ Data Structures MCQ 1](https://www.hackerrank.com/challenges/how-well-do-you-know-trees) | [Solution & Comment](solution/practice/data-structures/multiple-choice/how-well-do-you-know-trees/solution.py) 
 2 | [ Data Structures MCQ 2](https://www.hackerrank.com/challenges/are-you-an-expert-on-data-structures) | WIP
 3 | [ Data Structures MCQ 3](https://www.hackerrank.com/challenges/are-you-an-expert-on-data-structures-1) | WIP
 

From a46b9e9a12c7df70ab94488634555b67657c5a70 Mon Sep 17 00:00:00 2001
From: root <root@localhost.localdomain>
Date: Mon, 28 Oct 2019 16:09:56 +0000
Subject: [PATCH 16/20] Data Structure MCQ 2 Solution is added

---
 README.md       | 4 ++--
 challenges.json | 2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/README.md b/README.md
index 3ebe292..6ca53f4 100644
--- a/README.md
+++ b/README.md
@@ -501,7 +501,7 @@ Data Structures
 * [Queues](#queues) (0/5)
 * [Heap](#heap) (0/4)
 * [Disjoint Set](#disjoint-set) (4/4)
-* [Multiple Choice](#multiple-choice) (0/3)
+* [Multiple Choice](#multiple-choice) (2/3)
 * [Trie](#trie) (0/2)
 * [Advanced](#advanced) (1/48)
 
@@ -602,7 +602,7 @@ Data Structures
 \# | Challenge | Solution
 :---:|:---:|:---:
 1 | [ Data Structures MCQ 1](https://www.hackerrank.com/challenges/how-well-do-you-know-trees) | [Solution & Comment](solution/practice/data-structures/multiple-choice/how-well-do-you-know-trees/solution.py) 
-2 | [ Data Structures MCQ 2](https://www.hackerrank.com/challenges/are-you-an-expert-on-data-structures) | WIP
+2 | [ Data Structures MCQ 2](https://www.hackerrank.com/challenges/are-you-an-expert-on-data-structures) | [Solution & Comment](solution/practice/data-structures/multiple-choice/are-you-an-expert-on-data-structures/solution.py)
 3 | [ Data Structures MCQ 3](https://www.hackerrank.com/challenges/are-you-an-expert-on-data-structures-1) | WIP
 
 ### Trie
diff --git a/challenges.json b/challenges.json
index 13c1853..35a5bb4 100644
--- a/challenges.json
+++ b/challenges.json
@@ -3297,4 +3297,4 @@
       "name": "mathematics"
     }
   ]
-}
\ No newline at end of file
+}

From 76212e454d1a322e507cb9d86850bc409f3d8cc2 Mon Sep 17 00:00:00 2001
From: root <root@localhost.localdomain>
Date: Mon, 28 Oct 2019 16:15:29 +0000
Subject: [PATCH 17/20] Readmi.md fix

---
 .../are-you-an-expert-on-data-structures/solution.py             | 1 +
 1 file changed, 1 insertion(+)
 create mode 100644 solution/practice/data-structures/multiple-choice/are-you-an-expert-on-data-structures/solution.py

diff --git a/solution/practice/data-structures/multiple-choice/are-you-an-expert-on-data-structures/solution.py b/solution/practice/data-structures/multiple-choice/are-you-an-expert-on-data-structures/solution.py
new file mode 100644
index 0000000..2c9d9f0
--- /dev/null
+++ b/solution/practice/data-structures/multiple-choice/are-you-an-expert-on-data-structures/solution.py
@@ -0,0 +1 @@
+print("Segment Tree")

From 3d02d9b467cd5784a933204a34c8fb1f403314c8 Mon Sep 17 00:00:00 2001
From: root <root@localhost.localdomain>
Date: Mon, 28 Oct 2019 16:42:57 +0000
Subject: [PATCH 18/20] MCQ3 Solution is added

---
 .../are-you-an-expert-on-data-structures-1/solution.py           | 1 +
 1 file changed, 1 insertion(+)
 create mode 100644 solution/practice/data-structures/multiple-choice/are-you-an-expert-on-data-structures-1/solution.py

diff --git a/solution/practice/data-structures/multiple-choice/are-you-an-expert-on-data-structures-1/solution.py b/solution/practice/data-structures/multiple-choice/are-you-an-expert-on-data-structures-1/solution.py
new file mode 100644
index 0000000..5216b03
--- /dev/null
+++ b/solution/practice/data-structures/multiple-choice/are-you-an-expert-on-data-structures-1/solution.py
@@ -0,0 +1 @@
+print("Stack")

From af5d642a66fc9c14bfba201dc50507216dda7c1b Mon Sep 17 00:00:00 2001
From: root <root@localhost.localdomain>
Date: Wed, 30 Oct 2019 16:41:27 +0000
Subject: [PATCH 19/20] README.md Updated

---
 README.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/README.md b/README.md
index 6ca53f4..59f89b6 100644
--- a/README.md
+++ b/README.md
@@ -603,7 +603,7 @@ Data Structures
 :---:|:---:|:---:
 1 | [ Data Structures MCQ 1](https://www.hackerrank.com/challenges/how-well-do-you-know-trees) | [Solution & Comment](solution/practice/data-structures/multiple-choice/how-well-do-you-know-trees/solution.py) 
 2 | [ Data Structures MCQ 2](https://www.hackerrank.com/challenges/are-you-an-expert-on-data-structures) | [Solution & Comment](solution/practice/data-structures/multiple-choice/are-you-an-expert-on-data-structures/solution.py)
-3 | [ Data Structures MCQ 3](https://www.hackerrank.com/challenges/are-you-an-expert-on-data-structures-1) | WIP
+3 | [ Data Structures MCQ 3](https://www.hackerrank.com/challenges/are-you-an-expert-on-data-structures-1) | [Solution & Comment](solution/practice/data-structures/multiple-choice/are-you-an-expert-on-data-structures-1/solution.py)
 
 ### Trie
 \# | Challenge | Solution

From b6c0c199a5e320b1b59fdedafda2630258314b76 Mon Sep 17 00:00:00 2001
From: root <root@localhost.localdomain>
Date: Wed, 30 Oct 2019 17:17:08 +0000
Subject: [PATCH 20/20] Finla README.md Update

---
 README.md | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/README.md b/README.md
index 59f89b6..1190725 100644
--- a/README.md
+++ b/README.md
@@ -9,7 +9,7 @@ Index
 ======
 
 * [Algorithms](#algorithms) (61/409)
-* [Data Structures](#data-structures) (11/114)
+* [Data Structures](#data-structures) (17/114)
 * [Mathematics](#mathematics) (1/250)
 
 Algorithms
@@ -501,7 +501,7 @@ Data Structures
 * [Queues](#queues) (0/5)
 * [Heap](#heap) (0/4)
 * [Disjoint Set](#disjoint-set) (4/4)
-* [Multiple Choice](#multiple-choice) (2/3)
+* [Multiple Choice](#multiple-choice) (3/3)
 * [Trie](#trie) (0/2)
 * [Advanced](#advanced) (1/48)