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Grokking the Coding Interview Patterns in JavaScript

Solution: Find the Index of the First Occurrence in a String

Explore how to identify the first occurrence index of a substring within a given string using the sliding window technique. Learn to slide a fixed-size window and compare substrings efficiently, helping you solve common string search problems with clear time and space complexity understanding.

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Statement

Given two strings haystack and needle, return the index of the first occurrence of needle within haystack. If needle does not exist as a substring of haystack, return −1-1.

Constraints:

  • 1≤1 \leq haystack.length, needle.length ≤104\leq 10^4

  • haystack and needle consist of only lowercase English characters

Solution

The key intuition behind this solution is to use a fixed-size sliding window of length equal to needle ...