Leetcode 165 Compare Version Numbers

版权声明：本文为博主原创文章，未经博主允许不得转载。 https://blog.csdn.net/Neo233/article/details/85597283

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.

Example 1:

Input: version1 = "0.1", version2 = "1.1"Output: -1

Example 2:

Input: version1 = "1.0.1", version2 = "1"Output: 1

Example 3:

Input: version1 = "7.5.2.4", version2 = "7.5.3"Output: -1

这个题的意思是比较版本号的大小，就是一个字符串类的题目。

class Solution {
    public int compareVersion(String version1, String version2) {
        String[] ver1 = version1.trim().split("\\.");
        String[] ver2 = version2.trim().split("\\.");
        int len = Math.max(ver1.length,ver2.length);
        for(int i = 0 ; i < len ; i++){
    	Integer a = i < ver1.length ? Integer.parseInt(ver1[i]) : 0;
    	Integer b = i < ver2.length ? Integer.parseInt(ver2[i]) : 0;//1.0。0和1的问题
            int compare = a.compareTo(b);
            if(compare != 0){
                return compare;
            }
        }
        return 0;
    }
}