Compare Version Numbers

题目描述

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 < 1.11 < 1.21 < 13.371

题目解答

解题思路

算法思想：对

.

进行分割，然后逐个比较数字的大小

代码实现

public class Solution {
public int compareVersion(String version1, String version2) {
int len1 = version1.length();
int len2 = version2.length();

//注意是i < len1 || j < len2
for(int i = 0, j = 0; i < len1 || j < len2; i++, j++){
int num1 = 0;
while(i < len1 && version1.charAt(i) != '.'){
num1 = num1*10 + (version1.charAt(i)-'0');
i++;
}

int num2 = 0;
while(j < len2 && version2.charAt(j) != '.'){
num2 = num2*10 + (version2.charAt(j) -'0');
j++;
}

if(num1 > num2)
return 1;
else if(num1 < num2)
return -1;
}
return 0;
}
}