LeetCode Q165: Compare Version Number

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

	class Solution {
	public:
	int compareVersion(string v1, string v2) {
	if(v1.empty()&&v2.empty())
	return 0;
	string s1;
	int i1;
	int p1=0;
	while(v1[p1]!='.'&&p1<v1.length())
	s1=s1+string(1, v1[p1++]);
	p1=p1<v1.length()? p1+1:p1;
	i1=s1.empty()? 0:stoi(s1);
	string s2;
	int i2;
	int p2=0;
	while(v2[p2]!='.'&&p2<v2.length())
	s2=s2+string(1, v2[p2++]);
	p2=p2<v2.length()? p2+1:p2;
	i2=s2.empty()? 0:stoi(s2);
	if(i1==i2){
	return compareVersion(v1.substr(p1, v1.length()-p1), v2.substr(p2, v2.length()-p2));
	}
	if(i1>i2)
	return 1;
	if(i1<i2)
	return -1;
	}
	};

view raw Q165.cpp hosted with ❤ by GitHub

Round 2 solution:

	class Solution {
	public:
	int compareVersion(string version1, string version2) {
	int p1=0, p2=0;
	while(p1<version1.length()||p2<version2.length()){
	string d1, d2;
	while(version1[p1]!='.'&&p1<version1.length())
	d1=d1+version1[p1++];
	while(version2[p2]!='.'&&p2<version2.length())
	d2=d2+version2[p2++];
	int n1=d1.empty()? 0:stoi(d1);
	int n2=d2.empty()? 0:stoi(d2);
	if(n1>n2) return 1;
	if(n2>n1) return -1;
	p1++; p2++;
	}
	return 0;
	}
	};

view raw Q165Rnd2.cpp hosted with ❤ by GitHub