【Leetcode】【Easy】Compare Version Numbers

Compare two version numbers version1 and version2.
If version1 > version2 return 1, if version1 < version2 return -1, otherwise return 0.

You may assume that the version strings are non-empty and contain only digits and the . character.
The . character does not represent a decimal point and is used to separate number sequences.
For instance, 2.5 is not "two and a half" or "half way to version three", it is the fifth second-level revision of the second first-level revision.

Here is an example of version numbers ordering:

0.1 < 1.1 < 1.2 < 13.37

解题：

题目的意思是，比较版本号的大小，2版本比1版本大，而2.10版本比2.5版本大；

分别取出小数点前和小数点后的数字做比较；

代码：

class Solution {
public:
    int compareVersion(string version1, string version2) {
        int len1 = version1.size(); 
        int len2 = version2.size();
        int num1 = 0;
        int num2 = 0;
        int i = 0; 
        int j = 0;
        while(i < len1 || j < len2) {
            while (i < len1 && version1[i] != '.') {
                num1 = num1 * 10 + (version1[i] - '0');
                i++;
            }

            while (j < len2 && version2[j] != '.') {
                num2 = num2 * 10 + (version2[j] - '0');
                j++;
            }

            if(num1 > num2) 
                return 1;
            else if (num1 < num2) 
                return -1;

            num1 = 0;
            num2 = 0;
            i++;
            j++;
        }

        return 0;
    }
};