Post order traversal of binary tree without recursion

Here’s the version with one stack and without a visited flag: private void postorder(Node head) { if (head == null) { return; } LinkedList<Node> stack = new LinkedList<Node>(); stack.push(head); while (!stack.isEmpty()) { Node next = stack.peek(); boolean finishedSubtrees = (next.right == head || next.left == head); boolean isLeaf = (next.left == null && next.right == … Read more