Compare Version Numbers

题目

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.

答案

class Solution {
    public int compareVersion(String version1, String version2) {
        String[] v1 = version1.split("\\.");
        String[] v2 = version2.split("\\.");
        if(v1.length == 0) v1 = new String[]{version1};
        if(v2.length == 0) v2 = new String[]{version2};

        int m = v1.length, n = v2.length;
        int ans = 0;
        for(int i = 0; i < Math.max(m, n); i++) {
            int num1 = 0, num2 = 0;
            if(i < m) num1 = Integer.parseInt(v1[i]);
            if(i < n) num2 = Integer.parseInt(v2[i]);
            if(num1 > num2) return 1;
            else if(num1 < num2) return -1;
        }
        return 0;
    }
}