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

Explore how to efficiently find the index of the first occurrence of a substring within a larger string by applying the sliding window technique, comparing fixed-size windows step-by-step to identify matches.

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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 ...