[LeetCode]36. Compare Version Numbers版本号比较
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
解法:将version string拆分为一个个整数,从前往后对比即可。
class Solution { public: int compareVersion(string version1, string version2) { vector<string> vs1 = split(version1, '.'); vector<string> vs2 = split(version2, '.'); int s1 = vs1.size(), s2 = vs2.size(); if (s1 == 0 && s2 == 0) return 0; else if (s1 == 0 || s2 == 0) return s2 == 0 ? 1 : -1; else { int i, j; for (i = 0, j = 0; i < s1 && j < s2; ++i, ++j) { if (stoi(vs1[i]) < stoi(vs2[j])) return -1; if (stoi(vs1[i]) > stoi(vs2[j])) return 1; } while (i < s1) if (stoi(vs1[i++]) > 0) return 1; while (j < s2) if (stoi(vs2[j++]) > 0) return -1; return 0; } } private: vector<string> split(const string& str, const char delim) { vector<string> res; int start = 0, i = 0; for (int i = 0; i < str.size(); ++i) { if (str[i] == delim) { string s(str.begin() + start, str.begin() + i); if (!s.empty()) res.push_back(s); start = i + 1; } } string s(str.begin() + start, str.end()); if (!s.empty()) res.push_back(s); return res; } };