def postorder_evaluate(tree: BinaryTree):
opers = {
'+': operator.add,
'-': operator.sub,
'*': operator.mul,
'/': operator.truediv
}
if tree:
res1 = postorder_evaluate(tree.getLeftChild())
res2 = postorder_evaluate(tree.getRightChild())
if res1 and res2:
return opers[tree.getRootVal()](res1, res2)
else:
return tree.getRootVal()
def evaluate(parseTree: BinaryTree):
opers = {
'+': operator.add,
'-': operator.sub,
'*': operator.mul,
'/': operator.truediv
}
leftC = parseTree.getLeftChild()
rightC = parseTree.getRightChild()
if leftC and rightC:
fn = opers[parseTree.getRootVal()]
return fn(evaluate(leftC), evaluate(rightC))
else:
return parseTree.getRootVal()
def build_tree_condition(elements):
if len(elements) == 1:
return elements[0]
tree = BinaryTree('')
for i in range(len(elements)):
if type(elements[i]) is BinaryTree:
if tree.getRootVal() == '':
tree.insertLeft(elements[i])
else:
tree.insertRight(elements[i])
elif tree.getRootVal() in ['AND', 'OR', 'or', 'and']:
new_tree = BinaryTree('')
new_tree.setRootVal(elements[i])
new_tree.insertLeft(tree)
tree = new_tree
else:
tree.setRootVal(elements[i])
return tree
def buildParseTree(fpexp):
fplist = fpexp.split() #splitting a string of expression into list
#(type list)
pStack = Stack() #create empty stack
#(type 'instance')
eTree = BinaryTree('') #top root value
#(type 'instance')
pStack.push(eTree) #pushed current root into the stack
print pStack.size()
currentTree = eTree #current position at a time
#(type 'instance')
for i in fplist:
if i == '(':
currentTree.insertLeft('') #inserts an empty node as a leftChild
#print currentTree
pStack.push(currentTree) #pushes current tree into the stack
print 'StackSize: {}, root: {} iteration(push): {} '.format(
pStack.size(), currentTree.getRootVal(), i)
currentTree = currentTree.getLeftChild(
) #sets current position to the leftChild
elif i not in ['+', '-', '*', '/', ')']:
print '-----before root: {} '.format(currentTree.getRootVal())
currentTree.setRootVal(
int(i)
) #we are located at the node so set the root value to the number
#parent = pStack.pop() #???
#print 'StackSize: {}, parent: {} iteration(pop): digits'.format(pStack.size(), parent.getRootVal())
#currentTree = parent #this sets the current position to the parent node
currentTree = pStack.pop()
print 'StackSize: {}, iteration(pop): digits'.format(
pStack.size())
print '-----after root: {} '.format(currentTree.getRootVal())
elif i in ['+', '-', '*', '/']:
currentTree.setRootVal(
i) #set the value to the operator for "currentTree"
currentTree.insertRight('') # descend to the right child
pStack.push(
currentTree
) #push the new tree to the stack (will it push last updated node or the whole tree? Will it souble it?)
print 'StackSize: {}, root: {} iteration(push): {}'.format(
pStack.size(), currentTree.getRootVal(), i)
currentTree = currentTree.getRightChild(
) # this set the current position to the rightChild
elif i == ')':
currentTree = pStack.pop()
print 'StackSize: {}, root: {} iteration(pop)'.format(
pStack.size(), currentTree.getRootVal(), i)
else:
raise ValueError
print 'eTee root: {} '.format(eTree.getRootVal())
return eTree
def set_tree(text):
wtext = text.split()
pStack = Stack()
eTree = BinaryTree('')
pStack.push(eTree)
currentTree = eTree
currentTree.insertLeft('')
currentTree = currentTree.getLeftChild()
currentTree.setRootVal('1')
pStack.push(currentTree)
for i in wtext:
if BinaryTree.getRootVal(
currentTree) == '1' and not currentTree.isLeaf():
currentTree = pStack.pop()
currentTree.insertRight('')
currentTree = currentTree.getRightChild()
currentTree.setRootVal('2')
pStack.push(currentTree)
if i == '(':
currentTree.insertLeft('')
pStack.push(currentTree)
currentTree = currentTree.getLeftChild()
elif i not in ['(', ')']:
if currentTree.isLeaf():
if BinaryTree.getRootVal(currentTree) != '':
currentTree = pStack.pop()
currentTree.insertRight('')
currentTree = currentTree.getRightChild()
currentTree.setRootVal(i)
elif BinaryTree.getRootVal(currentTree) != None:
currentTree.setRootVal(i)
pStack.push(currentTree)
elif i == ')':
currentTree = pStack.pop()
currentTree = pStack.pop()
else:
raise ValueError
return eTree
def print_exp(tree: BinaryTree):
# 优化后的方法，去掉每个数字的左右括号
sVal = ''
if tree:
str_val = str(tree.getRootVal())
result = print_exp(tree.getLeftChild()) + str_val + print_exp(
tree.getRightChild())
if str_val.isnumeric():
sVal = result
else:
sVal = '(' + result + ')'
return sVal
def build_parse_tree(fpexp):
fplist = fpexp.split()
for i in fplist:
if i.__contains__('(') and i != '(':
index = fplist.index(i)
i_l = i.split('(')
fplist[index] = i_l[-1]
for j in range(len(i_l)-1):
fplist.insert(index, '(')
if i.__contains__(')') and i != ')':
index = fplist.index(i)
i_l = i.split(')')
fplist[index] = i.split(')')[0]
for j in range(len(i_l)-1):
fplist.insert(index+1, ')')
pstack = Stack()
current_tree = BinaryTree('')
current_tree.insertLeft('')
pstack.push(current_tree)
current_tree = current_tree.getLeftChild()
for i in fplist:
if i == '(':
current_tree.insertLeft('')
pstack.push(current_tree)
current_tree = current_tree.getLeftChild()
elif i not in ['and', 'or', ')']:
current_tree.setRootVal(i)
parent = pstack.pop()
current_tree = parent
elif i in ['and', 'or']:
if current_tree.getRootVal() != "":
pstack.push(current_tree)
current_tree = BinaryTree('')
current_tree.leftChild = pstack.pop()
current_tree.setRootVal(i)
current_tree.insertRight('')
pstack.push(current_tree)
current_tree = current_tree.getRightChild()
elif i == ')':
current_tree = pstack.pop()
else:
raise ValueError
return current_tree
def preorder(tree: BinaryTree):
# 前序遍历
if tree:
print(tree.getRootVal())
preorder(tree.getLeftChild())
preorder(tree.getRightChild())
def postorder(tree: BinaryTree):
# 后序遍历
if tree:
postorder(tree.getLeftChild())
postorder(tree.getRightChild())
print(tree.getRootVal())
def inorder(tree: BinaryTree):
# 中序遍历
if tree:
inorder(tree.getLeftChild())
print(tree.getRootVal())
inorder(tree.getRightChild())
def build_tree_expression(elements):
stack = Stack()
tree = BinaryTree('')
if len(elements) == 1:
tree.setRootVal(elements[0])
return tree
stack.push(tree)
for i in range(len(elements)):
if (elements[i] == '(') or (i == 0):
tree.insertLeft('')
if elements[i] == '(':
stack.push("(")
stack.push(tree)
tree = tree.getLeftChild()
if elements[i] != '(':
tree.setRootVal(elements[i])
parent = stack.pop()
tree = parent
elif elements[i] not in ['+', '-', '*', '/', ')']:
tree.setRootVal(elements[i])
parent = stack.pop()
tree = parent
elif elements[i] in ['+', '-', '*', '/']:
sign = elements[i]
if tree.getRootVal() in ['+', '-', '*', '/']:
if sign in ['+', '-'] or elements[i - 1] == ')':
temp = BinaryTree('')
parent = stack.pop()
if stack.size() == 0:
temp.insertLeft(parent)
parent = temp
tree = parent
stack.push(parent)
elif parent == "(":
temp.insertLeft(tree)
parent = stack.pop()
parent.insertRight(temp)
stack.push(parent)
stack.push("(")
tree = parent.getRightChild()
else:
temp.insertLeft(tree)
parent.insertRight(temp)
stack.push(parent)
tree = parent.getRightChild()
elif sign in ['*', '/']:
rChild = tree.getRightChild()
rChild.insertLeft(rChild.getRootVal())
tree = rChild
tree.setRootVal(elements[i])
tree.insertRight('')
stack.push(tree)
tree = tree.getRightChild()
elif elements[i] == ')':
parent = ""
while parent != "(":
parent = stack.pop()
if parent == "(":
tree = stack.pop()
stack.push(tree)
if i + 1 == len(elements):
for j in range(stack.size()):
parent = stack.pop()
tree = parent
return tree
r = BinaryTree('a')
print(r.getRootVal()) #a
print(r.getLeftChild()) #None
r.insertLeft('b')
print(r.getLeftChild()) #<__main__.BinaryTree object at 0x0000000005FFC780>
print(r.getLeftChild().getRootVal()) #b
r.insertRight('c')
print(r.getRightChild()) #<__main__.BinaryTree object at 0x0000000005DA2898>
print(r.getRightChild().getRootVal()) #c
r.getRightChild().setRootVal('hello')
print(r.getRightChild().getRootVal())
from pythonds.basic.stack import Stack
from pythonds.trees.binaryTree import BinaryTree
def buildParseTree(formula):
formulalist = formula.split() #['('，'3'，'+'，'('，'4'，'*'，'5'，')'，')']
rootStack = Stack() #用于跟踪父节点
Tree = BinaryTree('') #创建一个二叉树
rootStack.push(Tree)
currentTree = Tree
for i in formulalist:
if i == '(':
currentTree.insertLeft('')
rootStack.push(currentTree)
currentTree = currentTree.getLeftChild()
elif i not in ['+', '-', '*', '/', ')']:
currentTree.setRootVal(int(i))
parent = rootStack.pop()
cerrentTree = parent
