Find Nearest Right Node in Binary Tree

给一个二叉树和一个node, 找到这个node在二叉树的右边的节点.

这个题要用层序扫描.

/**
 * Definition for a binary tree node.
 * public class TreeNode {
 *     int val;
 *     TreeNode left;
 *     TreeNode right;
 *     TreeNode() {}
 *     TreeNode(int val) { this.val = val; }
 *     TreeNode(int val, TreeNode left, TreeNode right) {
 *         this.val = val;
 *         this.left = left;
 *         this.right = right;
 *     }
 * }
 */
class Solution {
    public TreeNode findNearestRightNode(TreeNode root, TreeNode u) {
        Queue<TreeNode> q = new LinkedList<>();
        q.add(root);
        while(!q.isEmpty()) {
            int size = q.size();
            boolean found = false;
            for(int i = 0; i < size; i++) {
                TreeNode node = q.poll();
                if(found)
                    return node;
                if(node.val == u.val)
                    found = true;
                if(node.left != null)
                    q.add(node.left);
                if(node.right != null)
                    q.add(node.right);
            }
        }
        return null;
    }
}