B"You're given an array of n integers between 0 and n inclusive. In one operation, you can choose any element of the array and replace it by the MEX of the elements of the array (which may change after the operation). For example, if the current array is [0, 2, 2, 1, 4] , you can choose the second element and replace it by the MEX of the present elements -- 3 . Array will become [0, 3, 2, 1, 4] . You must make the array non-decreasing, using at most 2n operations. It can be proven that it is always possible. Please note that you do not have to minimize the number of operations. If there are many solutions, you can print any of them. xe2 x80 x93 An array b[1 ldots n] is non-decreasing if and only if b_1 <= b_2 <= ldots <= b_n . The MEX (minimum excluded) of an array is the smallest non-negative integer that does not belong to the array. For instance: It's worth mentioning that the MEX of an array of length n is always between 0 and n inclusive. The first line contains a single integer t ( 1 <= t <= 200 ) -- the number of test cases. The description of the test cases follows. The first line of each test case contains a single integer n ( 3 <= n <= 1000 ) -- length of the array. The second line of each test case contains n integers a_1, ldots, a_n ( 0 <= a_i <= n ) -- elements of the array. Note that they don't have to be distinct. It is guaranteed that the sum of n over all test cases doesn't exceed 1000 . For each test case, you must output two lines: The first line must contain a single integer k ( 0 <= k <= 2n ) -- the number of operations you perform. The second line must contain k integers x_1, ldots, x_k ( 1 <= x_i <= n ), where x_i is the index chosen for the i -th operation. If there are many solutions, you can find any of them. Please remember that it is not required to minimize "...