关于在totoloto数组中验证相同数字的疑问

def check_duplicate_numbers(arr):
    for i in range(len(arr)):
        for j in range(i+1, len(arr)):
            if arr[i] == arr[j]:
                return True
    return False

totoloto = [1, 2, 3, 4, 5, 6]
has_duplicates = check_duplicate_numbers(totoloto)
print(has_duplicates)  # False

totoloto = [1, 2, 3, 4, 5, 5]
has_duplicates = check_duplicate_numbers(totoloto)
print(has_duplicates)  # True

def check_duplicate_numbers(arr):
    return len(arr) != len(set(arr))

totoloto = [1, 2, 3, 4, 5, 6]
has_duplicates = check_duplicate_numbers(totoloto)
print(has_duplicates)  # False

totoloto = [1, 2, 3, 4, 5, 5]
has_duplicates = check_duplicate_numbers(totoloto)
print(has_duplicates)  # True