Compare Version Numbers

Compare two version numbersversion1_and_version2. Ifversion1>version2_return1; ifversion1<version2_return-1;otherwise return0.

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,2.5is not "two and a half" or "half way to version three", it is the fifth second-level revision of the second first-level revision.

You may assume the default revision number for each level of a version number to be0. For example, version number3.4has a revision number of3and4for its first and second level revision number. Its third and fourth level revision number are both0.

Example

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

Example 4:

Input:
version1
 = "1.01", 
version2
 = "1.001"

Output:
 0

Explanation:
 Ignoring leading zeroes, both “01” and “001" represent the same number “1”

Example 5:

Input:
version1
 = "1.0", 
version2
 = "1.0.0"

Output:
 0

Explanation:
 The first version number does not have a third level revision number, 
 which means its third level revision number is default to "0"

Note

比较各个位置和总长度

Code

class Solution {
    public int compareVersion(String version1, String version2) {
        String[] v1 = version1.split("\\.");
        String[] v2 = version2.split("\\.");
        for (int i = 0; i < Math.max(v1.length, v2.length); i++) {
            int num1 = i < v1.length? Integer.parseInt(v1[i]) : 0;
            int num2 = i < v2.length? Integer.parseInt(v2[i]) : 0;
            if (num1 < num2) {
                return -1;
            }
            else if (num1 > num2) {
                return 1;
            }
        }
        return 0;        
    }

}