def nextGreaterElement(lst):
returnArr = [-1] * len(lst)
stack = myStack()
for x in range(len(lst)):
cur = lst[x]
while stack.isEmpty() is False and lst[stack.top()] < cur:
returnArr[stack.top()] = cur
stack.pop()
stack.push(x)
return returnArr
def evaluatePostFix(exp):
stack = myStack()
for char in exp:
if char.isdigit():
stack.push(char)
else:
right = stack.pop()
left = stack.pop()
res = str(eval(left + char + right))
stack.push(res)
return int(float(stack.pop()))
def isBalanced(exp):
stack = myStack()
map = {'{': '}', '[': ']', '(': ')'}
for char in exp:
if char in map:
stack.push(char)
else:
if char == map[stack.top()]:
stack.pop()
else:
return False
return stack.size() is 0
def sortStack(stack):
other_stack = myStack()
other_stack.push(stack.pop())
while stack.isEmpty() is False:
cur = stack.pop()
if other_stack.top() is not None and cur >= int(other_stack.top()):
other_stack.push(cur)
else:
while other_stack.isEmpty() is False:
stack.push(other_stack.pop())
other_stack.push(cur)
while other_stack.isEmpty() is False:
stack.push(other_stack.pop())
return stack
def reverseK(queue, k):
if queue.isEmpty() or k > queue.size() or k < 0:
return None
stack = myStack()
size = queue.size()
for x in range(k):
stack.push(queue.dequeue())
while stack.isEmpty() is False:
queue.enqueue(stack.pop())
for x in range(size - k):
queue.enqueue(queue.dequeue())
return queue
def __init__(self):
self.orderStack = myStack()
self.mainStack = myStack()
return None
def main():
theStack = myStack()
done = False
print("This program will match parentheses, brackets, and braces.")
print("The input can be anything. All symbols in the input", end = " ")
print("will be ignored except the parenthese, brackets, and braces.")
print("\nEnter any expression that contains parentheses, brackets, ")
inputString = input("and braces (empty string to quit): ")
if (inputString == ""):
done = True
while (not done):
for symbol in inputString:
# push left-hand symbols on the stack
if (symbol == '(' or symbol == '[' or symbol == '{'):
theStack.push(symbol)
# if we see a right-hand symbol, make sure the symbol
# on the top of the stack matches. If the stack is
# empty, then clearly they don't match
elif(symbol == ')'):
if (theStack.isEmpty()):
print ("Parentheses do not match.")
break
matchingSymbol = theStack.pop()
if (matchingSymbol != '('):
print ("Parentheses do not match.")
break
elif(symbol == ']'):
if (theStack.isEmpty()):
print ("Parentheses do not match.")
break
matchingSymbol = theStack.pop()
if (matchingSymbol != '['):
print ("Brackets do not match.")
break
elif(symbol == '}'):
if (theStack.isEmpty()):
print ("Parentheses do not match.")
break
matchingSymbol = theStack.pop()
if (matchingSymbol != '{'):
print ("Braces do not match.")
break
# else ... ignore all other symbols
# Once we are done processing the input, the stack had better be
# empty. If not, then there was an open symbol without a closing one.
if (not theStack.isEmpty()):
print("symbol", theStack.peek(), "was not closed")
# We need to empty the stack before processing the next input
# or else we will misinterpret a non-empty stack as an error
while (not theStack.isEmpty()):
theStack.pop()
else:
print("Parenthese, brackets, and braces match.")
print("\nEnter any expression that contains parentheses, brackets, ")
inputString = input("and braces (empty string to quit): ")
if (inputString == ""):
done = True
from Stack import myStack
def sortStack(stack):
other_stack = myStack()
other_stack.push(stack.pop())
while stack.isEmpty() is False:
cur = stack.pop()
if other_stack.top() is not None and cur >= int(other_stack.top()):
other_stack.push(cur)
else:
while other_stack.isEmpty() is False:
stack.push(other_stack.pop())
other_stack.push(cur)
while other_stack.isEmpty() is False:
stack.push(other_stack.pop())
return stack
# The outer and inner loops both traverse all the n elements of the stack. Hence, the time complexity is O(n2).
stacky = myStack()
stacky.push(19)
stacky.push(9)
stacky.push(9)
stacky.push(90)
sortStack(stacky)
def __init__(self):
# Can use size from argument to create stack
self.mainStack = myStack()
self.tempStack = myStack()
from Stack import myStack
s = myStack()
print(s.isEmpty())
s.push(1)
s.push("two")
print(s.peek())
s.push(True)
print(s.size())
print(s.isEmpty())
print(s.pop())
print(s.pop())
print(s.pop())
print(s.isEmpty())
print(" ")
from Queues import Queue
q = Queue()
print(q.size())
print(q.isEmpty())
q.enqueue(1)
q.enqueue(2)
print(q.dequeue())
print(" ")
from Deque import myDeque
d = myDeque()
d.addFront('1')
d.addRear('2')
print(d.size())
print(d.removeFront() + ' ' + d.removeRear())
print(d.size())
print(d.isEmpty())
def __init__(self):
self.mainStack = myStack()
self.sideStack = myStack()