Given a binary tree, print preorder traversal of it. The task is to complete the function preorder(), which accept root of the tree as argument.
For example: preorder traversal of below tree is "1 10 5 39"
1
/ \
10 39
/
5
Input:
The first line of input contains the number of test cases T. For every test case, the first line of input contains two space-separated integers, denoting node values for which we want to find LCA, and the second line will contain a string representing the tree as described below:
The values in the string are in the order of level order traversal of the tree where, numbers denote node values, and a character “N” denotes NULL child.
For example:
For the above tree, the string will be: 1 2 3 N N 4 6 N 5 N N 7 N
Output:
The function should print preorder traversal.
User Task:
Since this is a functional problem you don't have to worry about input, you just have to complete the function preorder() that prints the data in preorder way. The newline is automatically appended by the driver code.
Constraints:
1 <= T <= 200
1 <= Number of nodes <= 10^{4}
1 <= Data of a node <= 10^{5}
Example:
Input:
2
1 4 N 4 2
6 3 2 N 1 2
Output:
1 4 4 2
6 3 1 2 2
Explanation:
Testcase 1: There are 4 nodes in the tree. it looks like:
1
/
4
/ \
4 2
Its Preorder is 1 4 4 2
Testcase 2: In the similar way for the given input its preorder traversal will be 6 3 1 2 2 .
Note:The Input/Ouput format and Example given are used for system's internal purpose, and should be used by a user for Expected Output only. As it is a function problem, hence a user should not read any input from stdin/console. The task is to complete the function specified, and not to write the full code.
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