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

In this lesson, we will consider how to determine if a string is a palindrome permutation. 

Specifically:

Given a string, write a function to check if it is a permutation of a palindrome.

Recall: 

>**Palindrome**: A word or phrase that is the same forwards and backward. 

>**Permutation**: A rearrangement of letters.

The palindrome does not need to be limited to just dictionary words.

Before jumping straight to the code, let's think about how we can approach this problem. Here is an example of a palindrome:

From the slides above, the idea we get is that a string that has an even length must have all even counts of characters, while strings that have an odd length must have exactly one character with an odd count. An even-length-ed string can't have an odd number of exactly one character; otherwise, it wouldn't be even. This is true since an odd number plus any set of even numbers will yield an odd number. 

Alternatively, an odd-length-ed string can't have all characters with even counts, the sum of any number of even numbers is even. We can, therefore, say that it's sufficient to be a permutation of a palindrome, that is a string can have no more than one character that is odd. 

# Implementation

Let's make use of the observation discussed above regarding the palindrome property to implement the code in Python. We use a Python dictionary to solve the problem in the code below:

In this lesson, you will learn how to find if a string is a palindrome permutation or not. 

Introduction

Stack

Singly Linked Lists

Circular Linked Lists

Doubly Linked Lists

Arrays

Binary Trees

Binary Search Trees

Binary Search

Recursion

String Processing

Is Palindrome Permutation