Fast Fourier Transform, Algorithms, Pattern Matching, Convolution, Combination Sum.
consisting of lowercase english alphabets. Return all start indices in S where T is a substring of S. For e.g. if S = ‘mississippi‘ and T=’ssi’, then return [2, 5] because ‘ssi‘ occurs at indices 2 and 5 in S. One straightforward approach is to use sliding window i.e. slide T over S and at each