Given two strings `s` and `p`, return an array of all the start indices of `p`'s anagrams in `s`. You may return the answer in any order.

An Anagram is a word or phrase formed by rearranging the letters of a different word or phrase, typically using all the original letters exactly once.

Example 1:

    Input: s = "cbaebabacd", p = "abc"
    Output: [0,6]
    Explanation:
    The substring with start index = 0 is "cba", which is an anagram of "abc".
    The substring with start index = 6 is "bac", which is an anagram of "abc".

Example 2:

    Input: s = "abab", p = "ab"
    Output: [0,1,2]
    Explanation:
    The substring with start index = 0 is "ab", which is an anagram of "ab".
    The substring with start index = 1 is "ba", which is an anagram of "ab".
    The substring with start index = 2 is "ab", which is an anagram of "ab".

Constraints:

- `1 <= s.length, p.length <= 3 * 104`
- `s` and `p` consist of lowercase English letters.