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

Explore how to solve the problem of finding the first occurrence of a substring within a string using a fixed-size sliding window in Go. This lesson helps you understand direct substring comparison and implement an efficient search method while analyzing time and space complexities.

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:

  • 11 \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 ...