LeetCode: 28. Implement strStr()

Problem: 28. Implement strStr()

Link: https://leetcode.com/problems/implement-strstr/

Difficulty: Easy

Description:

Implement strStr().

Return the index of the first occurrence of needle in haystack, or -1 if needle is not part of haystack.

Example 1:

Input: haystack = “hello”, needle = “ll”
Output: 2

Example 2:

Input: haystack = “aaaaa”, needle = “bba”
Output: -1

Clarification:

What should we return when needle is an empty string? This is a great question to ask during an interview.

For the purpose of this problem, we will return 0 when needle is an empty string. This is consistent to C’s strstr() and Java’s indexOf().

Solution: 

Language: Swift

Runtime: 16ms
Memory: 19.4MB