[LeetCode] Compare Version Numbers 字符串操作

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

Credits:
Special thanks to @ts for adding this problem and creating all test cases.

Hide Tags

String

 

---

　　这题是太多细节的操作，字符串string 的操作其实很简单，主要判断0的情况，需要考虑1.1.0 与1.1 是相等的。代码写的有点冗余，如果再第一个while 中修改可以改短。

 

#include <iostream>

#include <string>

using namespace std;

class Solution {

public:

    int compareVersion(string version1, string version2) {

        if (version1.length()<||version2.length()<)   return ;

        int beg1 = ,beg2 = ;

        int end1 = ;

        int end2 = ;

        while(end1!=string::npos&&end2!=string::npos){

            end1 = version1.find_first_of('.',beg1);

            end2 = version2.find_first_of('.',beg2);

            int int1 = hFun(version1.substr(beg1,end1-beg1));

            int int2 = hFun(version2.substr(beg2,end2-beg2));

            if(int1 > int2) return ;

            if(int1 < int2) return -;

            beg1 = end1 +;

            beg2 = end2 +;

        }

        if(end1==string::npos){

            while(end2!=string::npos){

                end2 = version2.find_first_of('.',beg2);

                int int2 = hFun(version2.substr(beg2,end2-beg2));

                if(int2 >) return -;

                beg2 = end2+;

            }

        }

        if(end2==string::npos){

            while(end1!=string::npos){

                end1 = version1.find_first_of('.',beg1);

                int int1 = hFun(version1.substr(beg1,end1-beg1));

                if(int1 >) return ;

                beg1 = end1+;

            }

        }

        return ;

    }

    int hFun(string s)

    {

        int n = ;

        for(int i=;i<s.length();i++){

            n*=;

            n+=s[i]-'';

        }

        return n;

    }

};

int main()

{

    string version1 = "1.1";

    string version2 = "";

    Solution sol;

    cout<<sol.compareVersion(version1,version2)<<endl;

    return ;

}