T = int(input())

for i in range(T):
    R, S = input().split()
    R = int(R)
    s = ''
    for i in S:
        s += (i * R)
    print(s)

다시 푼 답

T = int(input())

for i in range(T):
    R, S = map(str, input().split())
    for s in S:
        print(s * int(R), end = '')
    print()

방법 1.

a = int(input())

for i in range(a):
  b, c = input().split()
  for i in range(len(c)):
    print(int(b) * c[i], end='')
  print()