class Queue(): def __init__(self): self.s1 = Stack() self.s2 = Stack() def Push(self, i): self.s1.Push(i) def Pop(self): while self.s1.IsEmpty() == False: self.s2.Push(self.s1.Pop()) outdat = self.s2.Pop() while self.s2.IsEmpty() == False: self.s1.Push(self.s2.Pop()) return outdat def Peek(self): while self.s1.IsEmpty() == False: self.s2.Push(self.s1.Pop()) outdat = self.s2.Peek() while self.s2.IsEmpty() == False: self.s1.Push(self.s2.Pop()) return outdat def IsEmpty(self): return self.s1.IsEmpty() def __repr__(self): return str(self.s1)[::-1]
def SortStack(s):
temp = Stack()
while s.IsEmpty() == False:
if temp.IsEmpty():
temp.Push(s.Pop())
if s.Peek() > temp.Peek():
hold = s.Pop()
s.Push(temp.Pop())
s.Push(hold)
elif s.Peek() <= temp.Peek():
temp.Push(s.Pop())
return temp
class Queue:
def __init__(self):
self.length = 0
self.s1 = Stack()
self.s2 = Stack()
def Insert(self, elem):
self.s1.Push(elem)
self.length += 1
def Remove(self):
if self.s2.Is_Empty():
#switch the entire stack over s2
while not self.s1.Is_Empty():
node = self.s1.Pop()
self.s2.Push(node)
elem = self.s2.Pop()
self.length -= 1
return str(elem)
def Is_Empty(self):
return self.length == 0
from stack import Stack
expression = "((A+(B*C))-D)"
# expression="(A+B*(C-D))"
results = ""
mystack = Stack()
for i in range(len(expression)):
if expression[i] >= "A" and expression[i] <= "Z":
results += expression[i]
else:
mystack.Push(expression[i])
if expression[i] == ")":
mystack.Pop() # pop ")"
while mystack.stack[mystack.top] != "(":
results += mystack.Pop()
mystack.Pop() # pop "("
print("postfix of expression\"{}\" is: {}".format(expression, results))
from stack import Stack
mystack = Stack()
mystack.stack = ['A', 'C', 'B', 'A', 'D', 'F', 0, 0, 0, 0]
mystack.top = 5
mystack.PrintStack()
tempstack = Stack()
for i in range(mystack.top + 1):
if mystack.stack[mystack.top] != "A":
tempstack.Push(mystack.Pop())
else:
mystack.Pop()
for j in range(tempstack.top + 1):
mystack.Push(tempstack.Pop())
tempstack.PrintStack() # should be empty
mystack.PrintStack()
"""
get the minimum value in a stack
"""
from stack import Stack
def MinStack(s):
lowest = s.Data[0]
for i in s.Data[1:]:
if i < lowest:
lowest = i
return lowest
if __name__ == '__main__':
test = Stack()
for i in [9,3,1,4,7,5,5,]:
test.Push(i)
print(test)
print('Minimum:\n')
print(MinStack(test))
from stack import Stack
# expression = "43-15*+"
expression = "15+2-6*"
mystack = Stack()
for i in range(len(expression)):
if expression[i] >= "0" and expression[i] <= "9":
mystack.Push(expression[i])
if expression[i] == "+":
mystack.Push(int(mystack.Pop()) + int(mystack.Pop()))
elif expression[i] == "-":
mystack.Push(-(int(mystack.Pop()) - int(mystack.Pop())))
elif expression[i] == "*":
mystack.Push(int(mystack.Pop()) * int(mystack.Pop()))
elif expression[i] == "/":
mystack.Push(int(mystack.Pop()) // int(mystack.Pop()))
print("\"{}\" = {}".format(expression, mystack.Pop()))
elif maze[x][y+1] == 0: # east
y += 1
go = True
elif maze[x+1][y] == 0: # south
x += 1
go = True
elif maze[x][y-1] == 0: # west
y -= 1
go = True
else: # dead end
go = False
print("Dead end...")
if go:
path_x.Push(x)
path_y.Push(y)
maze[x][y] = 2
else:
path_x.Pop()
path_y.Pop()
x, y = path_x.stack[path_x.top], path_y.stack[path_y.top]
print(">>> Maze solved! <<<")
print(np.matrix(maze))
