def _main():
"""
For testing.
"""
import os
import math
from algs4.stdlib import stdio, instream
_createTextAudioFile()
stdio.writeln('Creating and playing in small chunks...')
sps = _SAMPLES_PER_SECOND
inStream = instream.InStream('looney.txt')
while not inStream.isEmpty():
pitch = inStream.readInt()
duration = inStream.readFloat()
hz = 440 * math.pow(2, pitch / 12.0)
N = int(sps * duration)
notes = []
for i in range(N + 1):
notes.append(math.sin(2 * math.pi * i * hz / sps))
playSamples(notes)
wait()
stdio.writeln('Creating and playing in one large chunk...')
sps = _SAMPLES_PER_SECOND
notes = []
inStream = instream.InStream('looney.txt')
while not inStream.isEmpty():
pitch = inStream.readInt()
duration = inStream.readFloat()
hz = 440 * math.pow(2, pitch / 12.0)
N = int(sps * duration)
for i in range(N + 1):
notes.append(math.sin(2 * math.pi * i * hz / sps))
playSamples(notes)
wait()
stdio.writeln('Saving...')
save('looney', notes)
stdio.writeln('Reading...')
notes = read('looney')
stdio.writeln('Playing an array...')
playSamples(notes)
wait()
stdio.writeln('Playing a file...')
playFile('looney')
wait()
os.remove('looney.wav')
os.remove('looney.txt')
For additional documentation, see Section 4.4 of Algorithms, 4th Edition by Robert Sedgewick and Kevin Wayne.
"""
import sys
from algs4.stdlib import instream
from algs4.graphs.edge_weighted_digraph import EdgeWeightedDigraph
from algs4.graphs.directed_edge import DirectedEdge
from algs4.graphs.acyclic_lp import AcyclicLp
# Try this with the jobsPC.txt data file
if __name__ == '__main__':
# Create stream from file or the standard input,
# depending on whether a file name was passed.
file = sys.argv[1] if len(sys.argv) > 1 else None
stream = instream.InStream(file)
# Number of jobs
N = stream.readInt()
# Source and sink
source, sink = 2 * N, 2 * N + 1
# Construct the network
G = EdgeWeightedDigraph(2 * N + 2)
for i in range(N):
duration = stream.readFloat()
G.add_edge(DirectedEdge(i, i + N, duration))
G.add_edge(DirectedEdge(source, i, 0.0))
G.add_edge(DirectedEdge(i + N, sink, 0.0))
def has_cycle(self):
"""
Does the edge weighted digraph have a directed cycle?
:returns: true if there is a cycle, false otherwise
"""
return self._cycle != None
def cycle(self):
"""
Returns a directed cycle if the edge weighted digraph has a directed cycle, and null otherwise.
:returns: a directed cycle (as an iterable) if the digraph has a directed cycle, and null otherwise
"""
return self._cycle
import sys
from algs4.stdlib import instream
from algs4.graphs.edge_weighted_digraph import EdgeWeightedDigraph
if __name__ == '__main__':
# Create stream from file or the standard input,
# depending on whether a file name was passed.
stream = sys.argv[1] if len(sys.argv) > 1 else None
d = EdgeWeightedDigraph.from_stream(instream.InStream(stream))
cyc = EdgeWeightedDirectedCycle(d)
print(cyc.cycle())