BFS-2

Problem 1

Binary Tree Right Side View (https://leetcode.com/problems/binary-tree-right-side-view/)

class Solution {

public List rightSideView(TreeNode root) {

   List<Integer> result = new ArrayList<>();

   view(root,result,0);

   return result;

}

public void view(TreeNode root,List result,int depth){

   if(root==null) return;

   if(depth==result.size())

       result.add(root.val);

   view(root.right,result,depth+1);

   view(root.left,result,depth+1);

}

}

Problem 2

Cousins in binary tree (https://leetcode.com/problems/cousins-in-binary-tree/)

class Solution {

int x_depth=-1;

int y_depth=-1;

TreeNode x_parent=null;

TreeNode y_parent=null;

public boolean isCousins(TreeNode root, int x, int y) {

   calDepthAndParent(root,x,y,0,null);

   return x_depth == y_depth && x_parent!=y_parent;

}

public void calDepthAndParent(TreeNode root,int x,int y,int depth, TreeNode parent){

   if(root==null)

       return;

   if(root.val==x)

   {  x_parent=parent;

       x_depth=depth;}

   if(root.val==y)

   {y_parent=parent;

       y_depth=depth;}

   calDepthAndParent(root.left,x,y,depth+1,root);

   calDepthAndParent(root.right,x,y,depth+1,root);

}

}