#建立一個二叉樹
#聲明一個二叉樹節點類
#節點中包括:節點值,節點左子樹根節點,節點右子樹根節點,節點父節點
class TreeNode():
def __init__(self,value=None,leftNode=None,rightNode=None,parentNode=None):
self.val = value
self.leftnode = leftNode
self.rightnode = rightNode
self.parentnode = parentNode
def SetLeftNode(self,leftNode):
self.leftnode = leftNode
def SetRightNode(self,rightNode):
self.rightnode = rightNode
def SetParentNode(self,parentNode):
self.parentnode = parentNode
def GetLeftNode(self):
return self.leftnode
def GetRightNode(self):
return self.rightnode
def GetParentNode(self):
return self.parentnode
def GetValue(self):
return self.val
#定義根節點以及各個節點
root = TreeNode(1)
n2 = TreeNode(2)
n3 = TreeNode(3)
n4 = TreeNode(4)
n5 = TreeNode(5)
n6 = TreeNode(6)
n7 = TreeNode(7)
#設置根節點的左右節點
root.SetLeftNode(n2)
root.SetRightNode(n3)
#設置n2節點左右子樹節點和其父節點
n2.SetLeftNode(n4)
n2.SetRightNode(n5)
n2.SetParentNode(root)
#設置n3節點左右子樹節點和其父節點
n3.SetLeftNode(n6)
n3.SetRightNode(n7)
n3.SetParentNode(root)
#設置n4,n5節點的父節點
n4.SetParentNode(n2)
n5.SetParentNode(n2)
#設置n6,n7節點的父節點
n6.SetParentNode(n3)
n7.SetParentNode(n3)
#給了任意一個結點,輸出中序遍歷時,其下一個節點所存儲數值
#節點中序遍歷下一個節點有兩種情況:
#1、其爲它的右子樹的左子樹的最左子節點
#2、其爲它的父節點的左孩子時候的根節點
def GetNextNode(node):
if node.GetRightNode() != None:
node = node.GetRightNode()
while node.GetLeftNode()!=None:
node = node.GetLeftNode()
return node.GetValue()
else:
while node.GetParentNode() != None:
parentNode = node.GetParentNode()
if parentNode.GetLeftNode() == node:
return parentNode.GetValue()
node = parentNode
return None
#這裏輸出測試n3節點在中序遍歷時候的下一個節點->n7(值爲7)
print(GetNextNode(n3))
#這裏輸出測試n5節點在中序遍歷時候的下一個節點->n1(值爲1)
print(GetNextNode(n5))