add threads per timing plot

exercises/exerciseA/plot.py

@@ -7,6 +7,7 @@ threads, timings = [], []
 for file in os.listdir('timings'):
     with open(f'timings/{file}', 'r') as f:
         n, t = f.read().strip().split(',')
+        if n != 'None':
             threads.append(int(n))
             timings.append(float(t))
 threads = np.array(threads)
@@ -20,4 +21,10 @@ fig, axs = plt.subplots()
 # Remember to label your axis
 # Feel free to make it pretty
 
+
+axs.scatter(threads, timings)
+axs.set_xlabel("Number of Threads")
+axs.set_ylabel("Timings in seconds")
+axs.grit = True
+
 plt.savefig('threads_v_timings.png', dpi=300)