Example 1:
Input: s = "abcabc", pattern = "abc"
Output: [0, 3]
Explanation:
Example 2:
Input: s = "aaaa", pattern = "aa"
Output: [0, 1, 2]
Explanation:
Example 3:
Input: s = "hello", pattern = "xyz"
Output: []
Explanation:
Given a string s and a non-empty pattern pattern, return every starting index i in s where the substring s[i..i + pattern.length - 1] equals pattern.
Return the indices in ascending order. Overlapping matches are allowed — a match at index i does not prevent another match at index i + 1.
In the original interview framing, the candidate was asked to write a generator that yields a signal each time a substring of s matches the pattern. Returning the list of start indices is the equivalent non-streaming form.
The pattern appears at positions 0 and 3.
Overlapping matches count — aa starts at indices 0, 1, and 2.
No substring of s equals pattern.
0 <= s.length <= 10^41 <= pattern.length <= 10^3s and pattern consist of printable ASCII characters