두 갈래 나무의 선착순, 중착순, 후착순 (귀속과 비귀속)

순서대로 옮겨다니기 (귀속)

def preOrderTraverse(node):
    if node is None:
        return None
    print(node.val)
    preOrderTraverse(node.left)
    preOrderTraverse(node.right)

순서대로 옮겨다니기 (비귀속)

def preOrderTravese(node):
    stack = [node]
    while len(stack) > 0:
        print(node.val)
        if node.right is not None:
            stack.append(node.right)
        if node.left is not None:
            stack.append(node.left)
        node = stack.pop()

중간 순서로 옮겨다니기 (귀속)

def inOrderTraverse(node):
    if node is None:
        return None
    inOrderTraverse(node.left)
    print(node.val)
    inOrderTraverse(node.right)

중간 순서로 옮겨다니기 (비귀속)

def inOrderTraverse(node):
    stack = []
    pos = node
    while pos is not None or len(stack) > 0:
        if pos is not None:
            stack.append(pos)
            pos = pos.left
        else:
            pos = stack.pop()
            print(pos.val)
            pos = pos.right

뒷순서 반복 (귀속)

def postOrderTraverse(node):
    if node is None:
        return None
    postOrderTraverse(node.left)
    postOrderTraverse(node.right)
    print(node.val)

뒷순서 반복 (비귀속)

#  （ ）
#  
#  ： -> -> 
#  ：  -> -> ( ： -> -> )
#  
#  
def postOrderTraverse(node):
    stack = [node]
    stack2 = []
    while len(stack) > 0:
        node = stack.pop()
        stack2.append(node)
        if node.left is not None:
            stack.append(node.left)
        if node.right is not None:
            stack.append(node.right)
    while len(stack2) > 0:
        print(stack2.pop().val)

두 갈래 나무 노드 개수

def treeNodenums(node):
    if node is None:
        return 0
    nums = treeNodenums(node.left)
    nums += treeNodenums(node.right)
    return nums + 1