Find the Index of the First Occurrence
EasyString
Description
Given two strings needle and haystack, return the index of the first occurrence of needle in haystack, or -1 if needle is not part of haystack.
Examples
Input:
haystack = "sadbutsad", needle = "sad"Output:
0Explanation:
Searching 'sadbutsad' for 'sad': found at index 0 (s-a-d-b...) and index 6 (s-a-d). Returning the first occurrence: 0.
Input:
haystack = "programming", needle = "gram"Output:
3Explanation:
"gram" occurs at index 3 in "programming". The substring match starts at position 3: p-r-o-g-r-a-m-m-i-n-g.
Input:
haystack = "hello", needle = "world"Output:
-1Explanation:
"world" does not appear anywhere in "hello", so the result is -1.
Constraints
- •
1 ≤ haystack.length, needle.length ≤ 10⁴
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