Tree: Preorder Traversal
Problem Statement :
Complete the preorder function in the editor below, which has 1 parameter: a pointer to the root of a binary tree. It must print the values in the tree's preorder traversal as a single line of space-separated values.
Input Format
Our test code passes the root node of a binary tree to the preOrder function.
Constraints
1 <= Nodes in the tree <= 500
Output Format
Print the tree's preorder traversal as a single line of space-separated values.
Sample Input
1
\
2
\
5
/ \
3 6
\
4
Sample Output
1 2 5 3 4 6
Solution :
Solution in C :
In Java :
/* you only have to complete the function given below.
Node is defined as
class Node {
int data;
Node left;
Node right;
}
*/
void Preorder(Node root) {
if (root == null) { return; }
System.out.print(root.data + " ");
Preorder(root.left);
Preorder(root.right);
}
In C ++ :
void Preorder(node *root) {
if (!root) return;
printf("%d ", root->data);
Preorder(root->left);
Preorder(root->right);
}
In C :
/* you only have to complete the function given below.
node is defined as
struct node {
int data;
struct node *left;
struct node *right;
};
*/
void preOrder( struct node *root) {
if(root == NULL){
return;
}
else{
printf("%d ",root->data);
preOrder(root->left);
preOrder(root->right);
}
}
In python3 :
class node:
def __init__(self, val):
self.val = val
self.left = None
self.right = None
def addleft(self, val):
self.left = node(val)
def addright(self, val):
self.right = node(val)
"""
def parseInput(vals, root):
if vals:
val = vals.pop()
if val:
root.addleft(val)
parseInput(vals, root.left)
if vals:
val = vals.pop()
if val:
root.addright(val)
parseInput(vals, root.right)
"""
n = int(input())
vals = list(map(int, input().split()))
#vals = [6, 5, 3, 0, 0, 2, 0, 0, 4, 1]
vals.reverse()
root = node(vals.pop())
#parseInput(vals, root)
if n == 6:
root.addleft(vals.pop())
root.addright(vals.pop())
root.left.addleft(vals.pop())
root.left.addright(vals.pop())
root.right.addleft(vals.pop())
if n == 15:
root.addleft(vals.pop())
root.addright(vals.pop())
root.left.addleft(vals.pop())
root.left.addright(vals.pop())
root.right.addleft(vals.pop())
root.right.addright(vals.pop())
root.left.left.addleft(vals.pop())
root.left.left.addright(vals.pop())
root.left.right.addleft(vals.pop())
root.left.right.addright(vals.pop())
root.right.left.addleft(vals.pop())
root.right.left.addright(vals.pop())
root.right.right.addleft(vals.pop())
root.right.right.addright(vals.pop())
#user code here:
"""
just implement the preorder method below.
root is of type node, which is defined as:
class node:
def __init__(self, val):
self.val = val
self.left = None
self.right = None
"""
def preorder(root):
if root:
print(root.val,end = ' ')
preorder(root.left)
preorder(root.right)
#end user code
preorder(root)
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