package main

import (
	"fmt"
)

func main() {
	var t int
	if _, err := fmt.Scan(&t); err != nil {
		return
	}
	for i := 0; i < t; i++ {
		var n int
		fmt.Scan(&n)

		arr := make([]byte, 60)
		for j := 0; j < 60; j++ {
			arr[j] = 'a'
		}

		fmt.Println(string(arr))
		for j := 0; j < n; j++ {
			var a int
			fmt.Scan(&a)
			arr[a] = (arr[a]-'a'+1)%26 + 'a'
			fmt.Println(string(arr))
		}
	}
}