[LeetCode] 14. Longest Common Prefix

思路:
思路很直接, 先判断前两个字符串的公共前缀, 然后拿这个前缀和下一个字符串继续匹配, 一直循环下去

string LCPOfTwo(string& str1, string& str2) {    int len1 = str1.length(), len2 = str2.length();    if (len1 < len2) return LCPOfTwo(str2, str1);    string prefix = "";    for (int i = 0; i < len1; i++) {        if (str1[i] == str2[i]) prefix += str1[i];        else return prefix;    }    return prefix;}string longestCommonPrefix(vector<string>& strs) {    int size = strs.size();    if (! size) return "";    if (size == 1) return strs[0];    string prefix = strs[0];    for (int i = 1; i < size; i++) {        prefix = LCPOfTwo(prefix, strs[i]);    }    return prefix;}