题目
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.
答案
class Solution {
public List<Integer> rightSideView(TreeNode root) {
if(root == null) return new ArrayList<Integer>(); ;
Queue<TreeNode> q = new LinkedList<TreeNode>();
List<Integer> list = new ArrayList<Integer>();
q.offer(root);
while(q.size() != 0) {
int curr_size = q.size();
for(int i = 0; i < curr_size; i++) {
TreeNode t = q.poll();
if(i == curr_size - 1) list.add(t.val);
if(t.left != null) q.offer(t.left);
if(t.right != null) q.offer(t.right);
}
}
return list;
}
}
