Discover data structures and algorithms using Python. Gain insights into solving real-world problems and typical interview questions with detailed reviews, explanations, and hands-on coding exercises.

Data structures and algorithms are among the most fundamental concepts of Computer Science. Whether it’s real-world problems you’re trying to solve or the typical coding question asked in an interview, almost every problem requires you to demonstrate a deep understanding of data structures and algorithms. 

This course is a detailed review of some of the most common data structures and algorithms that you’ll see in interviews and your everyday work. With implementation details, thorough explanations, and hands-on coding exercises, you’ll quickly gain the confidence you need to solve any problem, no matter the situation.

Data Structures and Algorithms in Python

The code below is an implementation of  the `Node` class for which of the following linked lists?
```python
class Node:
    def __init__(self, data):
        self.data = data
        self.next = None
        self.prev = None
```

The code below is an implementation of the <code>Node</code> class for which of the following linked lists?
<pre><code class="language-python">class Node:
 def __init__(self, data):
 self.data = data
 self.next = None
 self.prev = None
</code></pre>

What is the output of the following code?

```python
class DoublyLinkedList:
  	...
  def delete(self, key):
          cur = self.head
          while cur:
              if cur.data == key:
                  if cur.next:
                      nxt = cur.next 
                      prev = cur.prev
                      prev.next = nxt
                      nxt.prev = prev
                      cur.next = None 
                      cur.prev = None
                      cur = None
                      return
                  else:
                      prev = cur.prev 
                      prev.next = None 
                      cur.prev = None 
                      cur = None 
                      return 
              cur = cur.next

dllist = DoublyLinkedList()
dllist.append(1)
dllist.append(2)
dllist.append(3)

dllist.delete(3)
dllist.delete(1)

dllist.print_list()          
```

What is the output of the following code?
<pre><code class="language-python">class DoublyLinkedList:
 	...
 def delete(self, key):
 cur = self.head
 while cur:
 if cur.data == key:
 if cur.next:
 nxt = cur.next 
 prev = cur.prev
 prev.next = nxt
 nxt.prev = prev
 cur.next = None 
 cur.prev = None
 cur = None
 return
 else:
 prev = cur.prev 
 prev.next = None 
 cur.prev = None 
 cur = None 
 return 
 cur = cur.next

dllist = DoublyLinkedList()
dllist.append(1)
dllist.append(2)
dllist.append(3)

dllist.delete(3)
dllist.delete(1)

dllist.print_list() 
</code></pre>

Doubly Linked List has more efficient methods to insert and delete elements than singly linked lists. 

Doubly Linked List has more efficient methods to insert and delete elements than singly linked lists.

The `next` attribute of the previous node in the doubly linked list

The `data` attribute of the previous node in the doubly linked list

The previous node in the doubly linked list

The `prev` attribute of a Node object is supposed to point to which of the following?

The <code>prev</code> attribute of a Node object is supposed to point to which of the following?

What is the output of the following code?
```python
class DoublyLinkedList:
     ...
	def print_list(self):
        cur = self.head
        while cur.next:
            cur = cur.next
        
        while cur:
            print(cur.data)
            cur = cur.prev


dllist = DoublyLinkedList()
dllist.prepend(0)
dllist.append(1)
dllist.append(2)
dllist.append(3)
dllist.append(4)
dllist.prepend(5)

dllist.print_list()
```

What is the output of the following code?
<pre><code class="language-python">class DoublyLinkedList:
 ...
	def print_list(self):
 cur = self.head
 while cur.next:
 cur = cur.next
 
 while cur:
 print(cur.data)
 cur = cur.prev


dllist = DoublyLinkedList()
dllist.prepend(0)
dllist.append(1)
dllist.append(2)
dllist.append(3)
dllist.append(4)
dllist.prepend(5)

dllist.print_list()
</code></pre>

It's quiz time! Test yourself by solving these questions about doubly linked lists.

Introduction

Stack

Singly Linked Lists

Circular Linked Lists

Doubly Linked Lists

Arrays

Binary Trees

Binary Search Trees

Binary Search

Recursion

String Processing

Quiz