Is Subsequence

class Solution:
    def isSubsequence(self, s1: str, s2: str) -> bool:
        i=0
        j=0
        while i<len(s1) and j<len(s2):
            if s1[i]==s2[j]:
                i+=1
                j+=1
            else:
                j+=1
        if i==len(s1):
            return True
        else:
            return False

'''
M:2 find the LCS of s1 and s2, if the LCS is s1 means s1 is the LCS of the S2 and the reason is longest LCS of s1 and s2 can the s1 only if len(s1)<=len(s2)
'''