Solution: Substring with Concatenation of All Words
Explore how to apply the sliding window technique to identify all starting indices of substrings composed of concatenated words from a given list. Understand how uniform word length enables consistent window strides and use frequency maps to manage word counts efficiently. This lesson helps you implement an optimized solution that moves window boundaries dynamically to handle extra or invalid words, improving your problem-solving skills in coding interviews.
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Statement
You are given a string, s, and an array of strings, words. All strings in words are of the same length.
A concatenated string is a string that contains all the words in words exactly once, in any order, concatenated together without any intervening characters.
Formally, a concatenated string is a permutation of all words joined together. For example, if words = ["ab", "cd", "ef"], then the following are all valid concatenated strings: "abcdef", "abefcd", "cdabef", "cdefab", "efabcd", "efcdab". However, "acdbef" is not valid because it is not formed by concatenating all the words in any order.
Your task is to return all starting indices of substrings in s that are concatenated strings.
You may return the indices in any order.
Constraints:
s.length...