class Solution {public:    int compareVersion(string version1, string version2) {        vector<int> v1 = getVersionParts(version1);        vector<int> v2 = getVersionParts(version2);        int i = 0, j = 0;        int len1 = v1.size();        int len2 = v2.size();        while (i < len1 && j < len2) {            if (v1[i] < v2[i]) {                return -1;            } else if (v1[i] > v2[i]) {                return 1;            }            i++, j++;        }        int r = 0;        while (i < len1) {            r += v1[i++];        }        if (r != 0) {            return 1;        }        r = 0;        while (j < len2) {            r += v2[j++];        }        if (r != 0) {            return -1;        }        return 0;    }    vector<int> getVersionParts(string& version) {        vector<int> parts;        int len = version.length();        int v = 0;        char d = ‘\0‘;        for (int i=0; i<len; i++) {            d = version[i];            if (d == ‘.‘) {                parts.push_back(v);                v = 0;                continue;            }            v = v * 10 + d - ‘0‘;        }        if (d != ‘.‘) {            parts.push_back(v);        }        return parts;    }};

class Solution {public:    int compareVersion(string version1, string version2) {        int part1 = 0;        int part2 = 0;        int len1 = version1.length();        int len2 = version2.length();                int i = 0, j = 0;        while (i < len1 || j < len2) {            char ch;            while (i < len1 && (ch = version1[i++]) != ‘.‘) {                part1 += ch - ‘0‘ + part1 * 10;            }            while(j < len2 && (ch = version2[j++]) != ‘.‘) {                part2 += ch - ‘0‘ + part2 * 10;            }            if (part1 > part2) {                return 1;            } else if (part1 < part2) {                return -1;            } else {                // part equal, continue to compare next version part            }            part1 = part2 = 0;        }                return 0;    }};