165. Compare Version Numbers - jiejackyzhang/leetcode-note GitHub Wiki

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

String类题目。

解题思路为先将String按"."转换为String[]，再转换为数字进行比较。

public class Solution {
    public int compareVersion(String version1, String version2) {
        if(version1 == null && version2 == null) return 0;
        if(version1 == null || version2 == null) return version1 == null ? -1 : 1;
        String[] list1 = version1.split("\\."); //String.split(String regex)
        String[] list2 = version2.split("\\.");
        int i = 0;
        while(i < list1.length || i < list2.length) {
            int num1 = i < list1.length ? Integer.valueOf(list1[i]) : 0;
            int num2 = i < list2.length ? Integer.valueOf(list2[i]) : 0;
            if(num1 < num2) {
                return -1;
            } else if(num1 > num2) {
                return 1;
            }
            i++;
        }
        return 0;
    }
}
⚠️ **GitHub.com Fallback** ⚠️