Consider the following set of processes, with the length of CPU burst given in the table. The processes are assumed to have arrived in the order P1, P2, P3, P4. Draw the Gantt chart that illustrates the execution of these processes using the following scheduling algorithms and calculate the average waiting time.

(1) First Come First Served (FCFS).

(2) Shortest Job First (SJF).

(3) Shortest-Remaining-Time-First (SRTF).

(4) Round Robin (RR, quantum=3ms).

\begin{tabular}{|c|c|c|} \hline Process & CPU Burst Time/ms & Arrive Time \\ \hline P1 & 7 & 0 \\ \hline P2 & 5 & 1 \\ \hline P3 & 1 & 3 \\ \hline P4 & 2 & 4 \\ \hline \end{tabular}