595 B | 595 chars
import sys
from math import sqrt, pi, sin, factorial
inp = lambda : sys.stdin.readline()[:-1].strip()
mii = lambda x = " " : [*map(int,inp().split(x))]
mfi = lambda x = " " : [*map(float,inp().split(x))]
ii = lambda : int(inp())
fi = lambda : float(inp())
p = print
def solve():
chk = [i for i in range(26)]
n = ii()
l = mii()
ans = []
for crt in l:
ans.append(chk[crt])
chk = [chk[crt]] + chk[:crt] + chk[crt+1:]
for i in ans:
print(end=chr(97+i))
print()
if __name__ == "__main__":
tc = ii()
for t in range(1, tc+1):
ret = solve()