Write a function to find the longest common prefix string amongst an array of strings.

Solution:

class Solution {public:    string longestCommonPrefix(vector
     
       &strs) {        int len = 0, n = strs.size(), MaxL = 0;        if(n == 0) return "";        else if(n == 1) return strs[0];                for(int i = 0;i < n;i++)            if(strs[i].length() > MaxL)                MaxL = strs[i].length();                bool flag = true;        while(flag)        {            if(len >= MaxL)                 break;                        for(int i = 0;i < n;i++)            {                if(strs[i][len] == strs[0][len])                    continue;                else                {                    flag = false;                    break;                }            }                        if(flag == true)                len++;        }                return strs[0].substr(0, len);    }};