(a) What does the code fragment compute? Give a computationally equivalent algorithm Pl with a linear worst-case running time. (b) procedure P1 (integer n; array A[0..n-1] of integer); S: 0; for i: 0 to n 1 loop S: S+A[0]; for j=1 to i loop S: S+All end loop; end loop; return S; end P1; procedure P2 (integer n); for i 1 to n loop while > 0 loop x: x-2.1; end loop; end loop; end P2;