1. Strict binary tree :

$\rightarrow$ Every node of tree must have either 0 or 2 child

2. Complete binary tree :

$\rightarrow$ CBT of $l$ levels must have $l-1$ levels fully occupied

$\rightarrow l^{th}$ level nodes can be added left to right

$\rightarrow$ CBT of height h has $2^h$ to $2^{h+1}-1$ nodes

3. Full binary tree :

$\rightarrow$ Every node must have 0 or 2 child and all the leaf nodes must be at the same level.

$\rightarrow$ CBT of height h has $2^{h+1}-1$ nodes

$*$ Every FBT is CBT

$In\ question\ sometimes:$

$CBT\rightarrow ACBT$

$FBT\rightarrow CBT$