Cracking the Amazon D-E-shaw Snapdeal Interview: Anagram Palindrome Question

Table of Contents

1. Introduction
2. Understanding the Question
3. The Approach
4. Step 1: Frequency Calculation Using HashMap
5. Step 2: Checking for Valid Palindrome
6. Handling Even Length Strings
7. Handling Odd Length Strings
8. Implementation and Testing
9. Conclusion
10. FAQs

Introduction

Welcome to the 5th day of 100 Days of Code! Today, we will be discussing the topic of anagram palindromes. We will learn what they are and how to determine if a given string can be rearranged to form a palindrome. Let's dive in!

Understanding the Question

An anagram palindrome is a string that can be rearranged to form a palindrome. In other words, if we rearrange the characters of a given string, we should be able to obtain a palindrome. It is important to note that the given string itself might not be a palindrome. Our task is to check if the given string can be rearranged to form a palindrome.

The Approach

To solve this problem, we will use a simple technique involving a hashmap. We will follow the following steps:

1. Calculate the frequency of each character in the original string using a hashmap.
2. Check the number of odd occurrences in the hashmap.
3. Based on the length of the original string, determine if it can form an anagram palindrome.

Now, let's break down these steps further and implement them.

Step 1: Frequency Calculation Using HashMap

We begin by creating a hashmap to store the frequency of each character in the original string. For each character in the string, we traverse through it and increment the count in the hashmap.

Step 2: Checking for Valid Palindrome

After calculating the frequencies, we need to check if the given string can form a valid palindrome. We handle two cases based on the length of the original string:

Handling Even Length Strings

If the length of the string is even, each character should have an even frequency. In this case, we check if the odd count in the hashmap is zero.

Handling Odd Length Strings

If the length of the string is odd, there should be only one character with an odd frequency. In this case, we check if the odd count in the hashmap is one.

Implementation and Testing

Now, we can implement the above steps in our code. We will traverse through the hashmap and calculate the odd count. Based on the length of the string and the odd count, we will return true or false indicating if the given string can form an anagram palindrome.

After implementing the code, we should test it with various test cases to ensure its correctness.

Conclusion

In this article, we have learned about anagram palindromes and how to determine if a given string can be rearranged to form a palindrome. We explored a simple approach using a hashmap to calculate the frequencies and checked the conditions for a valid anagram palindrome. By following this approach and implementing it in code, we can successfully solve the given problem.

FAQs

Q1. What is an anagram palindrome?

An anagram palindrome is a string that can be rearranged to form a palindrome. It means that if we rearrange the characters of a given string, we should be able to obtain a palindrome.

Q2. Can the original string itself be a palindrome?

No, the original string may or may not be a palindrome. Our task is to check if the given string can be rearranged to form a palindrome.

Q3. What is the time complexity of the solution?

The time complexity of our solution is O(n), where n is the length of the input string. This is because we iterate through the string and the hashmap once, calculating the frequencies and checking for a valid anagram palindrome.

Q4. Can we solve this problem using other techniques?

Yes, there are other techniques to solve this problem as well. However, the approach we discussed, involving a hashmap, is a simple and efficient way to solve it.