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Find All Anagrams in a String

Explore how to find every start index of an anagram of one string within another by effectively tracking character frequencies. Learn to apply this pattern to recognize rearranged letter sequences, enhancing your problem-solving skills for coding interviews.

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:

  • 11\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.js in the following coding playground. The supporting code template provided in freq_track.js is meant to assist in developing your solution to the problem.

JavaScript
usercode > main.js
import tracker from "./freq_track.js";
export function findAnagrams(a, b){
// replace this placeholder return statement with your code
return [];
}
Find all Anagrams in a String