class BellmanFordSP:
def __init__(self, g, s):
self.dist_to = []
self.edge_to = []
self.on_q = []
self.queue = Queue()
self.cost = 0
for i in range(g.v):
self.dist_to.append(float('inf'))
self.edge_to.append(None)
self.on_q.append(None)
self.queue.enqueue(s)
self.on_q[s] = True
while not self.queue.is_empty() and not self.has_nagative_cycle():
v = self.queue.dequeue()
self.on_q[v] = False
self.relax(g, v)
def relax(self, g, v):
for e in g.adj[v]:
w = e.v_to
if self.dist_to[w] > self.dist_to[v] + e.weight:
self.dist_to[w] = self.dist_to[v] + e.weight
self.edge_to[w] = e
if not self.on_q[w]:
self.on_q[w] = True
self.queue.enqueue(w)
def bfs(self, g, s):
q = Queue()
q.enqueue(s)
self.marked[s] = True
while not q.is_empty():
v = q.dequeue()
for w in g.get_adj(v):
if not self.marked[w]:
self.edge_to[w] = v
self.marked[w] = True
q.enqueue(w)