There are different ways to look at a binary tree. The left view of a binary tree contains the set of nodes that will be visible if you look at the binary tree from the left side.

Given the root node of a binary tree, return an array containing the node elements in the left view, from top to bottom.

Testing

Input Format

The first line contains an integer T denoting the number of test cases.

For each test case, the input has 2 lines:

• The first line contains an integer n denoting the number of nodes in the tree (including the NULL nodes).
• The second line contains n space-separated integers that will form the binary tree. The integers follow level order traversal of the tree where -1 indicates a NULL node.

Output Format

For each test case, the output contains a line with space-separated integers representing the left view of the binary tree.

Sample Input

6
12
1 2 3 4 5 6 -1 -1 -1 7 -1 8
7
1 2 -1 4 -1 5 6
3
6 -1 4
7
8 -1 9 -1 10 11 12
5
28 14 11 -1 48
1
6

Expected Output

1 2 4 7
1 2 4 5
6 4
8 9 10 11
28 14 48
6

1 <= T <= 10
1 <= n <= 105
1 <= node value <= 106