def reverseList(self, head: ListNode) -> ListNode:
# reverse a linked list through iteraction using a stack
if head == None:
return None
node = head
node_stack = stack()
node_list = []
while node is not None:
node_stack.append(node)
node = node.next
while len(node_stack) > 1:
node = node_stack.pop()
node.next = node_stack[-1]
node_list.append(node)
else:
node = node_stack.pop()
node.next = None
node_list.append(node)
return node_list[0]
def evalRPN(self, tokens):
from collections import deque as stack
st = stack()
for ch in tokens:
if ch == '+':
st.append(st.pop() + st.pop())
elif ch == '*':
st.append(st.pop() * st.pop())
elif ch == '-':
y = st.pop()
x = st.pop()
st.append(x - y)
elif ch == '/':
flag = 1
y = st.pop()
x = st.pop()
st.append(int(float(x) / float(y)))
else:
st.append(int(ch))
return st.pop()
def __repr__(self):
s1 = "|{}|\n".format("-" * len(str(max(self.__data))))
for i in self.__data[::-1]:
s1 = s1 + "|" + str(i) + "|\n"
s1 = s1 + "|{}|\n".format("-" * len(str(max(self.__data))))
return s1
def __getitem__(self, index):
try:
return self.__data[index]
except IndexError as e:
return e
if __name__ == '__main__':
s = Stack()
s.push(34)
s.push(59)
s.push(21)
print(s)
print(s.pop())
s.push(45)
print(s)
print(s.pop())
print(s.pop())
print(s.pop())
print(s.pop())
s = stack([23, 45, 67])
print(s)
print(s[2])
print(s[3])
def __init__(self):
self._states = {}
self._stack = stack([])
import collections
from math import *
stack = collections.stack()
# FF:
# general int is 256bit, aka -2**255 ... 2**256-1
# other type obey 256bit as an element
# but also support bit 8, 16 and so on
# for overflow it goes to 1 (wrap)
def isAllReal():
# a symbolic or concolic
pass
# Symbolically executing an instruction
def sym_exec_ins(params, block, instr, func_call, current_func_name):
global MSIZE
global visited_pcs
global solver
global vertices
global edges
global g_src_map
global calls_affect_state
global data_source
stack = params.stack
mem = params.mem
memory = params.memory
def __init__(self):
"""
Initialize your data structure here.
"""
self.inbound = stack()
self.outbound = stack()
from collections import stack a = stack()