def get_running_time_binary(keys):
"""Returns the running time for the binary search function.
Uses target of -1.
Args:
keys (list): list of positive, consecutive integers (i.e. not
containing -1)
Returns:
(float): time in seconds required for the function to execute
once on the list keys.
"""
target = -1
start = time.time()
sf.binary_search(keys, target, 0, len(keys) - 1)
end = time.time()
return end - start
def plot_times(min_length, max_length, step):
"""Produces a plot comparing the worst case running times for binary search
and linear search on lists with length between min_length and max_length.
Returns:
None
"""
# As the book does it, function is forced to round to zero, because the
# float returned by time.time() only has 6 or so decimal places.
# Calling each more than once produces a better looking graph.
# Binary search is so fast that the book's suggested method of speed-testing
# doesn't even work on a reasonably fast desktop...
max_list = list(range(max_length))
len_keys = []
seconds_linear = []
seconds_binary = []
for i in range(min_length, max_length + 1, step):
keys = max_list[:i]
start = time.time()
for i in range(10):
sf.linear_search(keys, -1)
end = time.time()
seconds_linear.append(end - start)
## print(f"Linear:\n\tstart was {start}\n\tend was {end}")
start = time.time()
for i in range(10):
sf.binary_search(keys, -1, 0, len(keys))
end = time.time()
seconds_binary.append(end - start)
# pyplot calls
pyplot.plot(range(min_length, max_length + 1, step),
seconds_linear,
label='Linear search')
pyplot.plot(range(min_length, max_length + 1, step),
seconds_binary,
label='Binary search')
pyplot.legend(loc='upper center')
pyplot.xlabel('len(keys)')
pyplot.ylabel('Time in seconds')
pyplot.show()
def query_quakes(ids, data):
prompt = 'Earthquake ID (q to quit): '
key = input(prompt)
while key.lower() != 'q':
index = sf.binary_search(ids, key, 0, len(ids) - 1)
## index = sf.linear_search(ids, key) # for comparison. Will exceed default cpython max recursion depth for worst case i.e. not-found.
if index >=0:
print('Location: ' + str(data[index][:2]) + '\n' +
'Magnitude: ' + str(data[index][3]) + '\n' +
'Depth : ' + str(data[index][2]) + '\n')
else:
print('An earthquake with that ID was not found.')
key = input(prompt)
def test_not_found_binary_search(self):
"""Test that target is NOT found by binary search."""
pos = binary_search(self.my_list, -1)
self.assertTrue(pos == None)
def test_found_binary_search(self):
"""Test that target is found by binary search."""
pos = binary_search(self.my_list, 3)
self.assertEqual(pos, 1)