
Non-Linear Data Structure 533
15.3 TYPES OF BINARY TREE
Strictly binary tree: Fig. 15.4 shows a strictly binary tree. When every no-leaf node in a binary tree is
filled with left and right subtrees, the tree is called a strictly binary tree.
Fig. 15.4 Strictly binary tree
In Fig. 15.4 nodes A, C and D provide two nodes each, whereas Fig. 15.3 is not a strictly binary tree. It
is because nodes C and D have only one son. The binary tree also contains levels. The root of the tree
has level 0 and the level of the other nodes is always greater by one than of their father. As per the
figure, the node H is at level 3 and node E is at level 2.