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Directed graph with optional weight assignment .
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Containing graph auto-fill, dfs and bfs.
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A Safari authored Dec 14, 2018
1 parent 1c29a45 commit fa2eecd
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95 changes: 95 additions & 0 deletions graphs/Directed (Weighted) Graph
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from collections import deque
import random as rand
import math as math

# the dfault weight is 1 if not assigend but all the implementation is weighted

class DirectedGraph:
# enter True or False for this constructor
def __init__(self):
self.graph = {}

# adding vertices and edges
# note that self loops are not supported in undirected simpl graphs but it is in multigraphs
def add_pair(self, u, v, w = 1):
if self.graph.get(u):
if self.graph[u].count([w,v]) == 0:
self.graph[u].append([w, v])
else:
self.graph[u] = [[w, v]]
if not self.graph.get(v):
self.graph[v] = []
def remove_pair(self, u, v):
if self.graph.get(u):
for _ in self.graph[u]:
if _[1] == v:
self.graph[u].remove(_)

# if no destination is meant the defaut value is -1
def dfs(self, s = -2, d = -1):
if s == d:
return []
stack = []
visited = []
if s == -2:
s = list(self.graph.keys())[0]
stack.append(s)
visited.append(s)
ss = s

while True:
# check if there is any non isolated nodes
if len(self.graph[s]) != 0:
ss = s
for __ in self.graph[s]:
if visited.count(__[1]) < 1:
if __[1] == d:
visited.append(d)
return visited
else:
stack.append(__[1])
visited.append(__[1])
ss =__[1]
break

# check if all the children are visited
if s == ss :
stack.pop()
if len(stack) != 0:
s = stack[len(stack) - 1]
else:
s = ss

# check if se have reached the starting point
if len(stack) == 0:
return visited

# c is the count of nodes you want and if you leave it or pass -1 to the funtion the count
# will be random from 10 to 10000
def fill_graph_randomly(self, c = -1):
if c == -1:
c = (math.floor(rand.random() * 10000)) + 10
for _ in range(c):
# every vertex has max 100 edges
e = math.floor(rand.random() * 102) + 1
for __ in range(e):
n = math.floor(rand.random() * (c)) + 1
if n == _:
continue
self.add_pair(_, n, 1)

def bfs(self, s = -2):
d = deque()
visited = []
if s == -2:
s = list(self.graph.keys())[0]
d.append(s)
visited.append(s)
while d:
s = d.popleft()
if len(self.graph[s]) != 0:
for __ in self.graph[s]:
if visited.count(__[1]) < 1:
d.append(__[1])
visited.append(__[1])
return visited

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