Given two strings s and p, find all start indices of p's anagrams in s.
Example 1:
Input: s = "cbaebabacd", p = "abc"
Output: [0, 6]
Explanation: "cba" at index 0 and "bac" at index 6 are anagrams of "abc".
Example 2:
Input: s = "abab", p = "ab"
Output: [0, 1, 2]