Substring with Concatenation of All Words

Substring with Concatenation of All Words

Given a string s and an array of strings words where all strings in words are of the same length, find all starting indices of substring(s) in s that represent a concatenation of every string in words exactly once, in any order, without any intervening characters. Example: Input: s = "barfoothefoobarman", words = ["foo","bar"] Output: [0,9] Explanation: Substrings starting at index 0 and 9 are "barfoo" and "foobar" respectively, which are permutations of ["foo","bar"]. Constraints: 1 <= s.length <= 10,000 1 <= words.length <= 5,000 1 <= words[i].length <= 30 s and words[i] consist of lowercase English letters.
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