<prompt> Kutokana na kamba s na orodha ya maneno maneno, kupata wote kuanza faharisi ya substrings katika s ambayo ni concatenation ya kila neno katika maneno hasa mara moja bila wahusika yoyote ya kati.  <response>: This problem can be solved using a sliding window approach.First, we count the frequency of each word in words using a dictionary.Then, we iterate over all possible starting indices in s and maintain a window of length lenwordslenwords0, which is the total length of all words concatenated.At each position in the window, we check if the substring starting at that position can be formed by concatenating all words in words exactly once. To do this, we keep another dictionary to count the frequency of each word in the current window.If the current window matches the desired concatenation, we add the starting index to the result.Here is the Python code:def findSubstrings: str, words: Liststr - Listint: if not s or not words: return word_freq for word in words: word_freqword word_freq.getword, 0 1 word_len lenwords0 total_len word_len lenwords res for i in rangelens - total_len 1: window_freq j i while j i total_len: curr_word sj:jword_len if curr_word not in word_freq: break window_freqcurr_word window_freq.getcurr_word, 0 1 if window_freqcurr_word word_freqcurr_word: break j word_len if j i total_len: res.appendi return res 