Find the Needle
Intermediate
Return the index of the first occurrence of needle in haystack, or -1 if it does not occur. An empty needle occurs at index 0.
For haystack = "sadbutsad" and needle = "sad" the answer is 0; for needle = "leeto" in "leetcode" it is -1.
The starter code compares letter by letter at every start. It is correct but too slow on repetitive texts.
Examples
Example 1
Input:
find_needle('sadbutsad', 'sad')
Output:
0
Example 2
Input:
find_needle('leetcode', 'leeto')
Output:
-1
Constraints
0 <= len(haystack) <= 2000000 <= len(needle) <= 2000- Lower-case letters.
Theory
Go to TheoryKeywords
dsa-sheetadvanced-stringspattern-matching
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