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Grokking the Coding Interview Patterns in Python

Find All Anagrams in a String

Explore how to identify all starting positions of anagrams of one string within another by mastering frequency tracking and character permutations. Understand problem constraints and implement an optimized solution to solve anagram and permutation challenges effectively.

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Statement

Given two strings, a and b, return an array of all the start indexes of anagrams of b in a. We may return the answer in any order.

An anagram is a word or phrase created by rearranging the letters of another word or phrase while utilizing each of the original letters exactly once. For example, “act” is the anagram of “cat”, and “flow” is the anagram of “wolf”.

Constraints:

  • 1≤1\leq a.length, b.length ≤103\leq 10^3
  • Both a and b consist only of lowercase English letters.

Examples

Understand the problem

Let’s take a moment to make sure you’ve correctly understood the problem. The quiz below helps you to check if you’re solving the correct problem:

Find All Anagrams in a String

1.

What’s the correct output for the following inputs?

a = “abab”

b = “ab”

A.

[0]

B.

[0, 2]

C.

[0, 1, 2]

D.

[1, 2]

1 / 5

Figure it out

We have a game for you to play. Rearrange the logical building blocks to develop a clearer understanding of how to solve this problem.

Sequence - Vertical
Drag and drop the cards to rearrange them in the correct sequence.
1
2
3
4

Try it yourself

Implement your solution in main.py in the following coding playground. The supporting code template provided in freq_track.py is meant to assist in developing your solution to the problem.

Python
usercode > main.py
def find_anagrams(a, b):

  

  # Replace this placeholder return statement with your code

  return []
Find All Anagrams in a String