You are trying to find whether a sequence of characters is a subsequence of another sequence. A subsequence of a string is obtained by deleting zero or more symbols of that string. For example, RACECAR is a subsequence of QRAECCETCAURP. Give a linear algorithm that takes two sequences S' of length m and S of length n and decides whether S' is a subsequence of S. Prove its correctness. Please answer in the form of pseudo-code.