class Solution {

public:

    string longestCommonPrefix(vector<string>& strs) {

        string prefix;

        if(strs.size()==) return prefix;

        for(int i=; i<strs[].size(); i++)

        {

            int j = ;

            for( ; j<strs.size(); j++)

            {

                if(strs[j][i]==strs[][i]) continue;

                else break;

            }

            if(j==strs.size()) prefix.push_back(strs[][i]);

            else break;

        }

        return prefix;

    } //Vertical scanning.

};