LeetCode题解——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

Credits:

class Solution {
public:
    int compareVersion(string version1, string version2) {
        int num1 = 0;
        int num2 = 0;
        int i=0, j=0;
        int n1 = version1.size(), n2 = version2.size();
        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;
            if(num1>num2) return 1;
            
            num1 = 0;
            num2 = 0;
            i++;
            j++;
        }
        return 0;
        
    }
};