Longest Common Prefix

 

    string longestCommonPrefix(vector<string> &strs) {
        // Note: The Solution object is instantiated only once and is reused by each test case.
        if(strs.empty())
            return "";
        int last = strs[0].size();
        for(int i=1;i<strs.size();i++)
        {
            last = min(last,(int)strs[i].size());
            for(int j=0;j<last;j++)
            {
                if(strs[0][j]!=strs[i][j])
                {
                    last = j;
                    break;
                }
            }
        }
        return strs[0].substr(0,last);
    }