class Solution:
    """
    @param word: a non-empty string
    @param abbr: an abbreviation
    @return: true if string matches with the given abbr or false
    """
    def validWordAbbreviation(self, word, abbr):
        # write your code here


        #thinking process
        #we keep two pointer
        #pointer to track where we are on abbr
        #pointer to track where we are on word
        #if abbr is letter, than compare
        #if abbr is digit then, grab the whole number and increase j by the num. 
        #* to get the whole num value refer to Programming trick

        if not word or not abbr:
            return False

        i = 0 #pointer for the abbr
        j = 0 #pointer used for compare with word

        if len(word) < len(abbr):
            return False

        # "w1rd"
        # "word"
        while i < len(abbr):

            if abbr[i].isdigit():
                num = 0
                count = 1
                while i < len(abbr) and abbr[i].isdigit():
                    num = num * count + int(abbr[i])
                    i += 1
                    count *= 10

                j += num
            #current abbr is a letter
            else:
                if abbr[i] != word[j]:
                    return False
                i += 1
                j += 1


        if i == len(abbr) and j == len(word):
            return True
        return False