Problem 4: Subsequences Given a sequence X if there exists a strictly increasing sequence ,12, ,%) of indices of X such that for all j 1, 2, . . . , k, zy-Sj. (For example Z = B, C, D, B) is a subsequence of X = (A, B, C, B, D, A, B).) Given two sequences X and Y, find the longest common subsequence of the two sequences. = (zl ,T2, . . . ,z,n), a sequence Z =21:22, , zx) is a subsequence of X