LeetCode 408. Valid Word Abbreviation

原題網址：https://leetcode.com/problems/valid-word-abbreviation/

Given a non-empty string s and an abbreviation abbr, return whether the string matches with the given abbreviation.

A string such as "word" contains only the following valid abbreviations:

["word", "1ord", "w1rd", "wo1d", "wor1", "2rd", "w2d", "wo2", "1o1d", "1or1", "w1r1", "1o2", "2r1", "3d", "w3", "4"]

Notice that only the above abbreviations are valid abbreviations of the string "word". Any other string is not a valid abbreviation of "word".

Note:
Assume s contains only lowercase letters and abbr contains only lowercase letters and digits.

Example 1:

Given s = "internationalization", abbr = "i12iz4n":

Return true.

Example 2:

Given s = "apple", abbr = "a2e":

Return false.

方法：指針記錄匹配的長度。

public class Solution {
    public boolean validWordAbbreviation(String word, String abbr) {
        char[] wa = word.toCharArray();
        char[] aa = abbr.toCharArray();
        int i = 0;
        int j = 0;
        for(int k = 0; k < aa.length; k++) {
            if (Character.isAlphabetic(aa[k])) {
                i += j;
                j = 0;
                if (i >= wa.length || wa[i++] != aa[k]) return false;
            } else {
                j *= 10;
                j += (aa[k] - '0');
                if (j == 0) return false;
            }
        }
        i += j;
        j = 0;
        if (i != wa.length) return false;
        return true;
    }
}