从版本号中提取数字, 默认是0, 直到两个字符串都匹配完了, 仍然没有找到更大的, 则返回0(循环外)

class Solution {
    /**
     * 从版本号中提取数字, 默认是0, 直到两个字符串都匹配完了,
     * 仍然没有找到更大的, 则返回0(循环外)
     */
    public int compareVersion(String version1, String version2) {
        char[] s1 = version1.toCharArray();
        char[] s2 = version2.toCharArray();
        int i1 = 0, i2 = 0;
        while (i1 < s1.length || i2 < s2.length) {
            int num1 = 0, num2 = 0;
            for (; i1 < s1.length && s1[i1] != '.'; i1++) {
                num1 = (s1[i1] - '0') + num1 * 10;
            }
            i1++;
            for (; i2 < s2.length && s2[i2] != '.'; i2++) {
                num2 = (s2[i2] - '0') + num2 * 10;
            }
            i2++;
            if (num2 > num1) return -1;
            else if (num1 > num2) return 1;
        }
        return 0;
    }
}