Phone Number Combinations

/* dpw4112001 */

#include<bits/stdc++.h>
using namespace std;
#define pii pair<int,int>
#define MOD 1000000007
#define f first
#define i insert
#define all(x) x.begin(),x.end()
#define s second
#define pb push_back
#define MX 1000005
#define IO ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL)
#define int long long
string table[]={"","","abc","def","ghi","jkl","mno","pqrs","tuv","wxyz"};
vector<string> solve(int a[],int n)
{
    queue<string>q;
    vector<string>v;
    
    q.push("");
    while(!q.empty())
    {
        string now=q.front();
        q.pop();
        if(now.length()==n)
            v.push_back(now);
        else
        {
            for(auto letter:table[a[now.length()]])
                q.push(now+letter);
        }

    }
    return v;
}
int32_t main()
{IO;
    #ifndef ONLINE_JUDGE
        freopen("input.txt","r",stdin);
        freopen("output.txt","w",stdout);
    #endif
    int t=1;
    cin >>t ;
    while(t--)
    {
        int n;
        cin >> n;
        int a[n];
        for(int i=0;i<n;i++)
            cin >> a[i];
        vector<string>ans=solve(a,n);
        for(auto str:ans)
            cout<<str<<' ';

    }
    return 0;
}