【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

Solution：类似于split的方法把字符串解析, 遇到'.'就判断之前的sum1和sum2

class Solution {
public:
    int compareVersion(string version1, string version2) {
        int sum1=0,sum2=0;
        int n1=version1.size(),n2=version2.size();
        for(int i=0,j=0;i<n1||j<n2;i++,j++){
            while(i<n1&&version1[i]!='.'){
                sum1=sum1*10+version1[i]-'0';
                i++;
            }
            while(j<n2&&version2[j]!='.'){
                sum2=sum2*10+version2[j]-'0';
                j++;
            }
            if(sum1>sum2)return 1;
            else if(sum1<sum2)return -1;
            else{
                sum1=0;
                sum2=0;
            }
        }
        return 0;
    }
};