Leetcode#199binary Tree Right Side View

Binary Tree Right Side View

Total Accepted: 8075 Total Submissions: 30533 My Submissions

Question Solution

Given A binary tree, imagine yourself standing on the right side of it, return the values of the nodes you can SE E ordered from top to bottom.

For example:
Given The following binary tree,

1 <---/2 3 <---\ 5 4 <---

You should return [1, 3, 4] .

Credits:
Special thanks to @amrsaqr for adding this problem and creating all test cases.

Analysis, intuitively just consider the rightmost element, no then consider the left son, but the following conditions will occur

1

/  \

2 3

/

4

Our solution is to use the queue class in layers to put only the right node of each layer into the results list

public class Solution {

Public list<integer> Rightsideview (TreeNode root) {

List<integer> x=new arraylist<integer> ();

queue<treenode> queue = new linkedlist<treenode> ();

if (root!=null)

{

TreeNode Z=null;

TreeNode Y=null;

Queue.add (root);

Queue.add (z);

Boolean o=false;

while (Queue.peek ()!=null)

{

O=false;

Y=queue.element ();

X.add (Y.val);

while (Y!=null)

{

if (y.right!=null)

{

O=true;

Queue.add (Y.right);

}

if (y.left!=null)

{

O=true;

Queue.add (Y.left);

}

Queue.remove ();

Y=queue.element ();

}

if (o==true)

Queue.add (z);

Queue.remove ();

}

}

return x;

}

}

Leetcode#199binary Tree Right Side View