Python notes--implementation of several data structures: stacks, queues, and binary trees

At present, only three kinds of implementation, stacks, queues and two fork tree, which day to continue to fill it ~

Bishi Busy Dizzy ~ ~

1. Stack

#栈 class Stack:def __init__ (Self,size =): Self.stack = [] self.size = Size Self.top =-1 def setSize (self, size): Self . Size = Size Def isempty (self): if self.top = = -1:return True else:return False def isfull (self): if self.top +1 = self . Size:return True Else:return False def top (self): if Self.isempty (): Raise Exception ("Stackisempty") Else:return self. STACK[SELF.TOP] def push (self,obj): If Self.isfull (): Raise Exception ("StackOverflow") else:self.stack.append (obj) Self.top +=1 def pop (self): if Self.isempty (): Raise Exception ("Stackisempty") else:self.top-= 1 return Self.stack.pop () Def show (self): print (self.stack) s = Stack (5) s.push (1) s.push (2) S.push (3) S.push (4) S.push (5) S.show () S.pop () S.show ( ) S.push (6) s.show ()

Perform:

2. Queues

#队列 class Queue:def __init__ (Self,size =): Self.queue = [] self.size = Size Self.front = 0 self.rear = 0 def isempty (s ELF): return self.rear = = 0 def isfull (self): if (self.front-self.rear + 1) = = Self.size:return True else:return False Def (self): if Self.isempty (): Raise Exception ("Queueisempty") Else:return Self.queue[self.front] def last (self): I F Self.isempty (): Raise Exception ("Queueisempty") Else:return Self.queue[self.rear] def add (self,obj): If Self.isfull () : Raise Exception ("Queueoverflow") else:self.queue.append (obj) self.rear + 1 def Delete (self): if Self.isempty (): Raise Exception ("Queueisempty") Else:self.rear-=1 return Self.queue.pop (0) def show (self): print (self.queue) q = Queue (3) Q.ad D (1) q.add (2) q.show () Q.delete () q.show ()

3. Two fork Tree

#二叉树 class Binarytreenode:def __init__ (self,data,left,right): Self.left = left self.data = Data Self.right = Right class Binarytree:def __init__ (self): Self.root = None def maketree (self,data,left,right): Self.root = Binarytreenode (data, Left,right) #left. root = Right.root = None def isempty (self): If Self.root is None:return True else:return False def pre Order (SELF,R): If r.root are not none:print (r.root.data) If r.root.left are not None:self.preOrder (r.root.left) if R.root. Right isn't None:self.preOrder (r.root.right) def inorder (self,r): If R.root is not none:if r.root.left are not None:sel F.inorder (r.root.left) print (r.root.data) if R.root.right is not None:self.inOrder (r.root.right) def postorder (Self,r) : If R.root is not none:if r.root.left are not None:self.preOrder (r.root.left) If r.root.right are not None:self.preOrder (r.root.right) Print (r.root.data) def levelorder (self,a): Q = Queue () R = a while R was not None:print (R.root.data) if R.R Oot.left is not None:q.add (r.roOt.left) If R.root.right is not None:q.add (r.root.right) if Q.isempty (): Print ("empty") r = None Else:r = Q.delete () R = BinaryTree () RA = BinaryTree () ra.maketree (2,none,none) RB = BinaryTree () rb.maketree (3,none,none) r.maketree (1,RA,RB) p Rint ("Pre-Traversal") R.preorder (r) print ("Sequence traversal") R.inorder (r) print ("Sequential traversal") R.postorder (r) Print ("Level traversal") R.levelorder (R)

Run Result:

Follow-up implementation will be slowly fill ~ ~ The old will continue to improve, I hope everyone to give advice ~ ~