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Merge c84aca23a8 into fcf82a1eda

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Prakhar Mittal 2024-10-05 10:40:32 -07:00 committed by GitHub
commit 7fa47ea6e5
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1 changed files with 194 additions and 64 deletions
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258
graphs/directed_and_undirected_weighted_graph.py
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@ -14,6 +14,18 @@ class DirectedGraph:
# adding the weight is optional
# handles repetition
def add_pair(self, u, v, w=1):
"""
Adds a directed edge u->v with weight w.
>>> dg = DirectedGraph()
>>> dg.add_pair(-1,2)
>>> dg.add_pair(1,3,5)
>>> dg.add_pair(1,3,5)
>>> dg.add_pair(1,3,6)
>>> dg.all_nodes()
[-1, 2, 1, 3]
>>> dg.graph[1]
[[5, 3], [6, 3]]
"""
if self.graph.get(u):
if self.graph[u].count([w, v]) == 0:
self.graph[u].append([w, v])
@ -23,10 +35,36 @@ class DirectedGraph:
self.graph[v] = []
def all_nodes(self):
"""
Returns list of all nodes in the graph.
>>> dg = DirectedGraph()
>>> dg.all_nodes()
[]
>>> dg.add_pair(1,1)
>>> dg.all_nodes()
[1]
>>> dg.add_pair(2,3,3)
>>> dg.all_nodes()
[1, 2, 3]
"""
return list(self.graph)
# handles if the input does not exist
def remove_pair(self, u, v):
"""
Removes all edges u->v if it exists.
>>> dg = DirectedGraph()
>>> dg.remove_pair(1,2) # silently exits
>>> dg.add_pair(0,5,2)
>>> dg.graph[0]
[[2, 5]]
>>> dg.remove_pair(5,0)
>>> dg.graph[0]
[[2, 5]]
>>> dg.remove_pair(0,5)
>>> dg.graph[0]
[]
"""
if self.graph.get(u):
for _ in self.graph[u]:
if _[1] == v:
@ -34,42 +72,57 @@ class DirectedGraph:
# if no destination is meant the default value is -1
def dfs(self, s=-2, d=-1):
if s == d:
return []
"""
Performs depth first search from s to find d.
Returns the path s->d as a list.
Returns dfs from s if d is not found
>>> dg = DirectedGraph()
>>> dg.dfs()
[]
>>> dg.add_pair(1,1)
>>> dg.dfs(1,1)
[1]
>>> dg = DirectedGraph()
>>> dg.add_pair(0,1)
>>> dg.add_pair(0,2)
>>> dg.add_pair(1,3)
>>> dg.add_pair(1,4)
>>> dg.add_pair(1,5)
>>> dg.add_pair(2,5)
>>> dg.add_pair(5,6)
>>> dg.dfs(0,6)
[0, 2, 5, 6]
>>> dg.dfs(1,6)
[1, 5, 6]
>>> dg.dfs()
[0, 2, 5, 6, 1, 4, 3]
>>> dg.dfs(1,0)
[1, 5, 6, 4, 3]
"""
stack = []
visited = []
if s == -2:
s = next(iter(self.graph))
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 node in self.graph[s]:
if visited.count(node[1]) < 1:
if node[1] == d:
visited.append(d)
return visited
else:
stack.append(node[1])
visited.append(node[1])
ss = node[1]
break
# check if all the children are visited
if s == ss:
stack.pop()
if len(stack) != 0:
s = stack[len(stack) - 1]
if self.graph.get(s, None):
pass # -2 is a node
elif len(self.graph) > 0:
s = next(iter(self.graph))
else:
s = ss
return [] # Graph empty
stack.append(s)
# check if se have reached the starting point
if len(stack) == 0:
return visited
# Run dfs
while len(stack) > 0:
s = stack.pop()
visited.append(s)
# If reached d, return
if s == d:
break
# add not visited child nodes to stack
for _, ss in self.graph[s]:
if visited.count(ss) < 1:
stack.append(ss)
return visited
# c is the count of nodes you want and if you leave it or pass -1 to the function
# the count will be random from 10 to 10000
@ -84,12 +137,42 @@ class DirectedGraph:
self.add_pair(i, n, 1)
def bfs(self, s=-2):
"""
Performs breadth first search from s
Returns list.
>>> dg = DirectedGraph()
>>> dg.bfs()
[]
>>> dg.add_pair(1,1)
>>> dg.bfs(1)
[1]
>>> dg = DirectedGraph()
>>> dg.add_pair(0,1)
>>> dg.add_pair(0,2)
>>> dg.add_pair(1,3)
>>> dg.add_pair(1,4)
>>> dg.add_pair(1,5)
>>> dg.add_pair(2,5)
>>> dg.add_pair(5,6)
>>> dg.bfs(0)
[0, 1, 2, 3, 4, 5, 6]
>>> dg.bfs(1)
[1, 3, 4, 5, 6]
>>> dg.bfs()
[0, 1, 2, 3, 4, 5, 6]
"""
d = deque()
visited = []
if s == -2:
s = next(iter(self.graph))
if self.graph.get(s, None):
pass # -2 is a node
elif len(self.graph) > 0:
s = next(iter(self.graph))
else:
return [] # Graph empty
d.append(s)
visited.append(s)
# Run bfs
while d:
s = d.popleft()
if len(self.graph[s]) != 0:
@ -300,42 +383,60 @@ class Graph:
# if no destination is meant the default value is -1
def dfs(self, s=-2, d=-1):
if s == d:
return []
"""
Performs depth first search from s to find d.
Returns the path s->d as a list.
Returns dfs from s if d is not found
>>> ug = Graph()
>>> ug.dfs()
[]
>>> ug.add_pair(1,1)
>>> ug.dfs(1,1)
[1]
>>> ug = Graph()
>>> ug.add_pair(0,1)
>>> ug.add_pair(0,2)
>>> ug.add_pair(1,3)
>>> ug.add_pair(1,4)
>>> ug.add_pair(1,5)
>>> ug.add_pair(2,5)
>>> ug.add_pair(5,6)
>>> ug.dfs(0,6)
[0, 2, 5, 6]
>>> ug.dfs(1,6)
[1, 5, 6]
>>> ug.dfs()
[0, 2, 5, 6, 1, 4, 3]
>>> ug.dfs(1,0)
[1, 5, 6, 2, 0]
"""
stack = []
visited = []
if s == -2:
s = next(iter(self.graph))
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 node in self.graph[s]:
if visited.count(node[1]) < 1:
if node[1] == d:
visited.append(d)
return visited
else:
stack.append(node[1])
visited.append(node[1])
ss = node[1]
break
# check if all the children are visited
if s == ss:
stack.pop()
if len(stack) != 0:
s = stack[len(stack) - 1]
if self.graph.get(s, None):
pass # -2 is a node
elif len(self.graph) > 0:
s = next(iter(self.graph))
else:
s = ss
return [] # Graph empty
stack.append(s)
# check if se have reached the starting point
if len(stack) == 0:
return visited
# Run dfs
while len(stack) > 0:
s = stack.pop()
if visited.count(s) == 1:
continue
else:
visited.append(s)
# If reached d, return
if s == d:
break
# add not visited child nodes to stack
for _, ss in self.graph[s]:
if visited.count(ss) < 1:
stack.append(ss)
return visited
# c is the count of nodes you want and if you leave it or pass -1 to the function
# the count will be random from 10 to 10000
@ -350,10 +451,39 @@ class Graph:
self.add_pair(i, n, 1)
def bfs(self, s=-2):
"""
Performs breadth first search from s
Returns list.
>>> ug = Graph()
>>> ug.bfs()
[]
>>> ug.add_pair(1,1)
>>> ug.bfs(1)
[1]
>>> ug = Graph()
>>> ug.add_pair(0,1)
>>> ug.add_pair(0,2)
>>> ug.add_pair(1,3)
>>> ug.add_pair(1,4)
>>> ug.add_pair(1,5)
>>> ug.add_pair(2,5)
>>> ug.add_pair(5,6)
>>> ug.bfs(0)
[0, 1, 2, 3, 4, 5, 6]
>>> ug.bfs(1)
[1, 0, 3, 4, 5, 2, 6]
>>> ug.bfs()
[0, 1, 2, 3, 4, 5, 6]
"""
d = deque()
visited = []
if s == -2:
s = next(iter(self.graph))
if self.graph.get(s, None):
pass # -2 is a node
elif len(self.graph) > 0:
s = next(iter(self.graph))
else:
return [] # Graph empty
d.append(s)
visited.append(s)
while d: