Leetcode 165. 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

int compareVersion(string version1, string version2) {    int i = 0;     int j = 0;    int n1 = version1.size();     int n2 = version2.size();    int num1 = 0;    int num2 = 0;    while(i<n1 || j<n2)    {        while(i<n1 && version1[i]!='.'){            num1 = num1*10+(version1[i]-'0');            i++;        }        while(j<n2 && 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;}