Got you, thanks a lot.

Can you tell me how you noticed the problem in code and came up with a test to prove it?

I want to improve my CP skills, thanks!

I'm curious to know if anyone did this approach solving the problem A ??, because it keeps failing for me for some case, even though I tested it in with a lot of cases:

n = int(input())
tests = []
 
 
def no_one_repeat(array1, array2):
    for a, b in zip(array1, array2):
        if a == b:
            return False
    return True
 
 
for x in range(n):
    _ = input()
    tests.append(list(map(int, input().split())))
 
for test in tests:
    suppose_min = len(test)
    done = False
    while not done:
        array = [suppose_min — i for i in reversed(range(len(test)))]
        if no_one_repeat(test, array):
            print(suppose_min)
            done = True
        suppose_min += 1