$//$ Base case: if the node is null, the subtree is complete if $($node $==$ null$)\{$ return true; $\}//$ If the index is greater than or equal to the number of nodes, it's not complete if $($index $>=$ totalNodes$)\{$ return false; $\}//$ Recursively check the left and right subtrees $//$ Left child index $=2*$ index $+1//$ Right child index $=2*$ index $+2$ return isComplete$($node$.$left, $2*$ index $+1,$ totalNodes$)$ && isComplete$($node$.$right, $2*$ index $+2,$ totalNodes$)$;