5th_January.cpp

//User function Template for C++

class Solution
{
public:
    string longestString(vector<string> &words)
    {
        // code here
        unordered_map<string,int> m;
        
        sort(words.begin(), words.end());

        for(auto i:words) m[i]++;

        string ans;

        int size=INT_MIN;

        for(auto i:words){

            string temp;

            int c= 0, n=i.size();

            for(int j=0;j<n;j++){

                temp+=i[j];

                if(m[temp]) c++;

            }

            if(c==n && n>size){

                size=n;

                ans=i;

            }

        }

        return ans;
    }
};