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BinaryTreeRightSideView.java
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BinaryTreeRightSideView.java
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package problems.medium;
import problems.utils.TreeNode;
import java.util.ArrayList;
import java.util.LinkedList;
import java.util.List;
/**
* Created by sherxon on 1/9/17.
*/
public class BinaryTreeRightSideView {
/**
* Solution 1:
*/
public List<Integer> rightSideView(TreeNode root) {
if (root == null) return new ArrayList<>();
LinkedList<TreeNode> q = new LinkedList<>();
LinkedList<TreeNode> level = new LinkedList<>();
q.add(root);
level.add(root);
List<Integer> list = new ArrayList<>();
list.add(root.val);
while (!q.isEmpty()) {
TreeNode x = q.removeFirst();
if (x.left != null)
q.add(x.left);
if (x.right != null)
q.add(x.right);
level.removeFirst();
if (level.isEmpty() && !q.isEmpty()) {
for (TreeNode n : q)
level.add(n);
list.add(level.getLast().val);
}
}
return list;
}
/**
* Solution 2
*/
public List<Integer> rightSideView2(TreeNode root) {
List<Integer> result = new ArrayList<Integer>();
rightView(root, result, 0);
return result;
}
public void rightView(TreeNode curr, List<Integer> result, int currDepth) {
if (curr == null) {
return;
}
if (currDepth == result.size()) {
result.add(curr.val);
}
rightView(curr.right, result, currDepth + 1);
rightView(curr.left, result, currDepth + 1);
}
}