Populate Inorder Successor for all Nodes

Problem Statement

Populate Inorder Successor for all nodes | Practice | GeeksforGeeks

Pattern:

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Solution

public void populateNext(Node root){
	Deque<Node> stack = new LinkedList<>();
	Node node = root, pre = null;
	while(node!=null || !stack.isEmpty()) {
		if(node!=null){
			stack.push(node);
			node = node.left;
		} else {
			node = stack.pop();
			if(pre!=null) pre.next = node;
			pre = node;
			node = node.right;
		}
	}
}

Notes

• jsut a laggin pointer, pointing its next to the curr node ptr