def preOrderIterative(root):
if root == None:
return
stack1 = MyStack()
stack1.push(root)
while not stack1.isEmpty():
node = stack1.pop()
print(node.key)
if node.rightChild != None:
stack1.push(node.rightChild)
if node.leftChild != None:
stack1.push(node.leftChild)
def topoSort(graph):
stack = MyStack()
visited = set()
for vKey in graph.vertices:
vertex = graph.vertices[vKey]
if vertex in visited:
continue
else:
topUtil(vertex=vertex, visited=visited, stack=stack, graph=graph)
return stack
def reverseLevelOrder(root):
q = MyQueue()
stack = MyStack()
q.enqueue(root)
q.enqueue(None)
arr = [root.key]
stack.push(arr)
arr = []
while not q.isEmpty():
top = q.dequeue()
if top == None and q.size() >= 1:
"""if top is None and after dequeue, queue size is 0 (q.size() >=1 is false)
then tree traversal is finished"""
print("\n")
stack.push(arr)
arr = []
q.enqueue(top)
elif top:
if top.leftChild:
q.enqueue(top.leftChild)
arr.append(top.leftChild.key)
if top.rightChild:
q.enqueue(top.rightChild)
arr.append(top.rightChild.key)
# q.displayAllElements()
while not stack.isEmpty():
arr = stack.pop()
print(arr)
def __init__(self):
self.stack1 = MyStack()
self.stack2 = MyStack()
#self.stack1.push(ele)
self.currentStack = self.stack1
class queue():
def __init__(self):
self.stack1 = MyStack()
self.stack2 = MyStack()
#self.stack1.push(ele)
self.currentStack = self.stack1
def enqueue(self, ele):
if self.currentStack == self.stack1:
self.stack1.push(ele)
else:
while not self.stack2.isEmpty():
self.stack1.push(self.stack2.pop())
self.currentStack = self.stack1
self.stack1.push(ele)
self.displayAllElement()
def dequeue(self):
if self.currentStack == self.stack2:
self.stack2.pop()
else:
while not self.stack1.isEmpty():
self.stack2.push(self.stack1.pop())
self.currentStack = self.stack2
self.stack2.pop()
self.displayAllElement()
def getSize(self):
return self.currentStack.size()
def displayAllElement(self):
if self.currentStack == self.stack1:
self.stack1.displayAllElements()
else:
self.stack2.displayAllElementsInReverseOrder()
def check_Balance_Parant(str):
# Check is even number of brackets
if len(str) % 2 != 0:
return False
stack = MyStack()
for s in str:
if s == '{' or s == '[' or s == '(':
stack.push(s)
else:
if s == ')' and stack.peek() == '(':
stack.pop()
elif s == '}' and stack.peek() == '{':
stack.pop()
elif s == ']' and stack.peek() == '[':
stack.pop()
else:
return False
if stack.isEmpty():
return True
else:
return False
if child.color != Color.Grey:
dfsRec(graph, child)
return
else:
return
g = Graph()
g.addVertex("A")
g.addVertex("B")
g.addVertex("C")
g.addVertex("D")
g.addVertex("E")
g.addVertex("F")
g.addVertex("G")
g.addVertex("Z")
g.addEdge(fromVertex="A", toVertex="B", weight=50)
g.addEdge(fromVertex="A", toVertex="F", weight=50)
g.addEdge(fromVertex="B", toVertex="C", weight=50)
g.addEdge(fromVertex="B", toVertex="Z", weight=50)
g.addEdge(fromVertex="C", toVertex="D", weight=50)
g.addEdge(fromVertex="D", toVertex="E", weight=50)
g.addEdge(fromVertex="F", toVertex="G", weight=50)
g.addEdge(fromVertex="G", toVertex="H", weight=50)
stack = MyStack()
#dfs(g,g.vertices["A"],stack)
dfsRec(g, g.vertices["A"])