Compute the run time of the following. Show all work for full credit

a$.T(n)=\{\begin{array}{ccc}1& if& n=1\\ T(n-1)+n& if& n>1\end{array}$

b$.T(n)=\{\begin{array}{ccc}1& if& n=2^k\\ T(\frac{n}{2})+1& if& n>1\end{array}$