Algorithm for labeling the nodes of tree(DAG):
1. For Leaf Nodes
Assign label 1 to left child node and label 0 to right child node.
2. For Interior Nodes
Case 1: If Node's children's labels are different, then
Node's Label = Maximum among Children's Labels.
Case 2: If Node's children's labels are same, then
Node's Label = (Left Child's Label OR Right Child's Label) + 1.