PLEASE DRAW TREE. $OR$ SHOW $IN$ PAPER int recursive$($int n$)$

$\{$

if$($n$<=1)$

return n

sum $=0$;

for $($int i $=0$; i $<$ n; i$++)$ sum$++$

return recursive$($n$/3)+$ recursive$($n$/3)+$ recursive$($n$/2)+$ sum;

a$)[5$pts$]$ Give a recurrence relation $($T$($n$)=...)$ for this function. Include both base and recursive cases$)$

b$)[10$pts$]$ Solve the recurrence relation to get the $O(...)$ running time of the function, in terms of n$.$ Show

your work, using the substitution method and the PLEASE DRAW recursion tree.