Add InterviewCake.com examples

Adds some of the code I generated while studying for a role transfer at Google
using the fantastic resource, InterviewCake.com. This work predates the
mono-repo.

I should think of ways to DRY up this code and the code in
crack_the_coding_interview, but I'm afraid I'm creating unnecessary work for
myself that way.

data_structures_and_algorithms/plot.py

@@ -0,0 +1,9 @@
+import numpy as np
+import matplotlib.pyplot as plt
+
+rng = np.random.RandomState(10)  # deterministic random data
+a = np.hstack((rng.normal(size=1000), rng.normal(loc=5, scale=2, size=1000)))
+_ = plt.hist(a, bins='auto')  # arguments are passed to np.histogram
+plt.title("Histogram with 'auto' bins")
+Text(0.5, 1.0, "Histogram with 'auto' bins")
+plt.show()