Find start indices of anagram substrings

You are given two strings: - `s`: the text string - `p`: the pattern string Return a list of all starting indices `i` such that the substring `s[i : i + len(p)]` is a permutation (an anagram) of `p`. The indices can be returned in increasing order. ### Input - `s` and `p` contain only lowercase English letters. ### Output - An array/list of integers: all valid starting indices. ### Examples 1. `s = "cbaebabacd"`, `p = "abc"` → `[0, 6]` - `s[0:3] = "cba"` is an anagram of `"abc"` - `s[6:9] = "bac"` is an anagram of `"abc"` 2. `s = "abab"`, `p = "ab"` → `[0, 1, 2]` ### Constraints - `1 <= len(s) <= 3 * 10^4` - `1 <= len(p) <= 3 * 10^4` - `len(p) <= len(s)`