class Node():
def __init__(self,elem=-1,lchild=None,rchild=None):
self.elem = elem
self.lchild = lchild
self.rchild = rchild
class Tree():
def __init__(self,root=None):
self.root = root
def add(self,elem):
node = Node(elem)
if self.root == None:
self.root = node
else:
queue = []
queue.append(self.root)
while queue:
cur = queue.pop(0)
if cur.lchild == None:
cur.lchild = node
return
elif cur.rchild == None:
cur.rchild = node
return
else:
queue.append(cur.lchild)
queue.append(cur.rchild)
def preorder(self,root):
"""先序遍历"""
if root == None:
return
print(root.elem)
self.preorder(root.lchild)
self.preorder(root.rchild)
def inorder(self,root):
"""中序遍历"""
if root == None:
return
self.inorder(root.lchild)
print(root.elem)
self.inorder(root.rchild)
def postorder(self,root):
"""后序遍历"""
if root == None:
return
self.postorder(root.lchild)
self.postorder(root.rchild)
print(root.elem)
def breadth_travel(self,root):
"""利用队列实现树的层次遍历"""
if root == None:
return
queue = []
queue.append(root)
while queue:
node = queue.pop(0)
print(node.elem)
if node.lchild != None:
queue.append(node.lchild)
if node.rchild != None:
queue.append(node.rchild)
if __name__ == '__main__':
tree = Tree()
tree.add(1)
tree.add(2)
tree.add(3)
tree.add(4)
tree.add(5)
tree.add(6)
tree.add(7)
tree.add(8)
#先序遍历
tree.preorder(tree.root)
# 中序遍历
# tree.inorder(tree.root)
# 后续遍历
# tree.postorder(tree.root)
# 广度优先
# tree.breadth_travel(tree.root)
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