Given a list of contacts which exist in a phone directory and a query string str. The task is to implement search query for the phone directory.

                           Phone directory problem

Given a list of contacts which exist in a phone directory and a query string str. The task is to implement search query for the phone directory. Run a search query for each prefix p of the query string str(i.e from  index 1 to str length) that prints all the distinct recommended contacts which have the same prefix as our query (p) in lexicographical order.

NOTE: If there is no match between query and contacts , print "0".

print each query result in new line. If there is no match between query and contacts, print "0".

Example:
Input:
1
3
geeikistest geeksforgeeks geeksfortest
geeips

Output:

geeikistest geeksforgeeks geeksfortest
geeikistest geeksforgeeks geeksfortest
geeikistest geeksforgeeks geeksfortest
geeikistest
0
0

#include <bits/stdc++.h>
using namespace std;

int main() {
	//code
	int t;
	cin>>t;
	while(t--)
	{
	    int n,f;
	    cin>>n;
	    vector<string> v;
	    v.clear();
	    string s;
	    for(int i=0;i<n;++i)
	    {
	        cin>>s;
	        v.push_back(s);
	    }
	    cin>>s;
	     
	    int i=0;
//sort string in lexicographical ordered 
//so print the in lexicographical
	    sort(v.begin(),v.end());
//if there is duplicate element 
//then uniquify the vector
	   auto it=std::unique(v.begin(),v.end());
//resize the vector
	   v.resize(std::distance(v.begin(),it));
	 
	    while(i<s.size())
	    {
	        f=1;
//checking for every string 
	        for(int j=0;j<v.size();++j)
	        {
// char of s is same as char of v[j] at i position then print
//else vanise the string and set to null.
	            if(s[i]==v[j][i]&&v[j].size()>0)
	            {
	                cout<<v[j]<<" ";
	                f=0;
	            }
	           else{
	                v[j]="\0";
	            }
	        }
	          ++i;
//if not found any matching print just 0.
	        if(f)cout<<'0'<<" ";
	        
	       cout<<endl;
	        
	    }
	}
	return 0;
}