You are given an integer (n). Your task is to construct an array of length (2 \cdot n) such that: Each integer from (1) to (n) appears exactly twice in the array. For each integer (x) ((1 \le x \le n)), the distance between the two occurrences of (x) is a multiple of (x). In other words, if (p_x) and (q_x) are the indices of the two occurrences of (x), (| q_x - p_x |) must be divisible by (x). It can be shown that a solution always exists. Each test contains multiple test cases. The first line contains the number of test cases (t) ((1 \le t \le 10^4)). The description of the test cases follows. Each of the next (t) lines contains a single integer (n) ((1 \le n \le 2 \cdot 10^{5})). It is guaranteed that the sum of (n) over all test cases does not exceed (2 \cdot 10^{5}). For each test case, print a line containing (2 \cdot n) integers — the array that satisfies the given conditions. If there are multiple valid answers, print any of them. Visualizer link In the first test case: The number (1) appears at positions (1) and (3): the distance is (2), which is divisible by (1). The number (2) appears at positions (2) and (4): the distance is (2), which is divisible by (2). In the second test case: The number (1) appears at positions (1) and (3): the distance is (2), which is divisible by (1). The number (2) appears at positions (4) and (6): the distance is (2), which is divisible by (2). The number (3) appears at positions (2) and (5): the distance is (3), which is divisible by (3). In the third test case, the two occurrences of (1) are at positions (1) and (2), so the distance between them is (1), which is a multiple of (1).