Leetocde_Binary Tree Right Side View

Leetocde_Binary Tree Right Side View

Description:

 

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

For example:
Given the following binary tree,

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

 

You shoshould return[1, 3, 4].

Ideas:

Based on the Thought of sequential traversal, only the last element of the layer can be saved at a time.

Code:

 

public List
 
   rightSideView(TreeNode root) {        List
  
   listReturn=new ArrayList
   
    ();        if(root==null)        return listReturn;        List
    
     list=new ArrayList
     
      ();        List
      
       temp=new ArrayList
       
        (); list.add(root); TreeNode node=null; listReturn.add(root.val); while(list.size()!=0) { for(int i=0;i
        
         0) listReturn.add(temp.get(temp.size()-1).val); list.clear(); list=temp; temp=new ArrayList
         
          (); } return listReturn; }
         
        
       
      
     
    
   
  
 

 

Result: