408. Valid Word Abbreviation

注意 pay attention to the 0 before a digit!!!!

class Solution {
public:
    bool validWordAbbreviation(string word, string abbr) {
        int j = 0;
        for(int i = 0; i < abbr.size(); i++, j++) {
            int tmp = 0;
            while (i < abbr.size() && isdigit(abbr[i])) {
                if (tmp == 0 && abbr[i] == '0') return false;
                tmp = tmp * 10 + abbr[i++] - '0';
            }
            j += tmp;
            if (i == abbr.size()){
                if (j == word.size()) return true;
                return false;
            }
            if (j >= word.size() || word[j] != abbr[i]) return false;
        }
        return true;
    }
};