165. 比较版本号

题目链接

解题思路：

C++：

class Solution {
public:
    int compareVersion(string version1, string version2) {
        int n1 = version1.size(), n2 = version2.size(), end = max(n1, n2);
        for(int p1 = 0, p2 = 0; p1 < end || p2 < end; p1++, p2++) {
            unsigned int v1 = 0, v2 = 0;
            while (p1 < n1 && version1[p1] != '.') v1 = v1 * 10 + version1[p1++] - '0';
            while (p2 < n2 && version2[p2] != '.') v2 = v2 * 10 + version2[p2++] - '0';
            if (v1 > v2) return 1;
            else if (v1 < v2) return -1;
        }
        return 0;
    }
};