import random import queue # This file demonstrates a simple manipulation with a # binary tree data type. # Technically, a tree discussed here is a so-called rooted tree. # each node in a binary tree has at most two children, # left and right one, if they exist. # Optionally, see more data structure examples at # https://xlinux.nist.gov/dads/ # ............................................................................ # N O D E # ............................................................................ class Node: def __init__(self, key = 0): self.left = None self.right = None self.key = key self.xcoord = -1 self.mark = ' ' # one character def print(self): print( "[" + str(self.key) + "]", end = "" ) print( str(self.xcoord)+", ", end = "") # ............................................................................ # B I N A R Y T R E E # ............................................................................ class BinaryTree: def __init__(self, key ): self.root = Node( key ) def setTags(self, node, aMark ): if node == None: return node.mark = aMark self.setTags( node.left, aMark ) self.setTags( node.right, aMark ) def processInOrder(self, node): if (node == None): return self.processInOrder(node.left) print(node.key, end = " ") #node.print() self.processInOrder(node.right) def processPreOrder(self, node): if (node == None): return print(node.key, end = " ") self.processPreOrder(node.left) self.processPreOrder(node.right) def processPostOrder(self, node): if (node == None): return self.processPostOrder(node.left) self.processPostOrder(node.right) print(node.key, end = " ") def rndTree0(self, node, depth): if (depth <= 0 or random.randrange(10) > 7) : return None newnode = Node(10+random.randrange(90)) newnode.left = Node.rndTree0(depth-1) newnode.right = Node.rndTree0(depth-1) return newnode def rndTree(self, node, depth): node.key = 10+random.randrange(90) if depth <= 0: return node if random.randrange(0, 10) < 6: childNode = Node ( ) # empty node node.left = self.rndTree( childNode, depth-1 ) if random.randrange(0, 10) < 6: childNode = Node ( ) # empty node node.right = self.rndTree( childNode, depth-1 ) return node def count(self, node): if (node == None): return 0 return 1 + self.count(node.left) + self.count(node.right) def depth (self, node): if (node == None): return -1 return 1 + max(self.depth(node.left), self.depth(node.right)) # calculates x coord = node order of in Inorder traversal def setXcoord(self, node, x_coord): if node == None: return x_coord node.xcoord = self.setXcoord(node.left, x_coord) + 1 #print(node.key, node.setXcoord) return self.setXcoord(node.right, node.xcoord) def display(self): qu = queue.Queue() prevDepth = -1 prevEndX = -1 # in the queue store pairs(node, its depth) qu.put( (self. root, 0) ) while not qu.empty(): node, nodeDepth = qu.get() LbranchSize = RbranchSize = 0 if node.left != None: LbranchSize = (node.xcoord - node.left.xcoord) qu.put( (node.left, nodeDepth+1) ) if node.right != None: RbranchSize = (node.right.xcoord - node.xcoord) qu.put( (node.right, nodeDepth+1) ) LspacesSize = (node.xcoord - LbranchSize) - 1 # if first on a line if prevDepth == nodeDepth: # not first on line LspacesSize -= prevEndX # print the node, branches, leading spaces if prevDepth < nodeDepth and prevDepth > -1 : print() # next depth occupies new line nodelen = 3 print( " "*nodelen*LspacesSize, end = '' ) print( "_"*nodelen*LbranchSize, end = '' ) #print( "." + ("%2d"%node.key) + node.mark+".", end = '' ) print( node.mark + ("%2d"%node.key), end = '' ) print( "_"*nodelen*RbranchSize, end = '' ) # used in the next run of the loop: prevEndX = node.xcoord + RbranchSize prevDepth = nodeDepth # end of queue processing N = self.countNodes( self.root ) print("\n"+ '-'*N*nodelen) # finish the last line of the tree def displayMarked(self, nodesList, char): self.setTags( self.root, ' ' ) for quNode in nodesList: quNode.mark = '*' self.display() def countNodes(self, node): if node == None: return 0 return 1 + self.countNodes( node.left ) + self.countNodes( node.right ) def depth2 (self, node): if (node == None): return -1 node.mark = '*' self.display() return 1 + max(self.depth2(node.left), self.depth2(node.right)) def BFS(self): self.setTags( self.root, ' ' ) qu = queue.Queue() qu.put( self.root ) while not qu.empty(): node = qu.get() # remove front print( node.key, end = ' ' ) if node.left != None: qu.put( node.left ) if node.right != None: qu.put( node.right ) print() def BFS2(self): qu = queue.Queue() qu.put( self.root ) k = 0 while not qu.empty(): # display tree and highlight nodes in the queue self.displayMarked( qu.queue, '*') # process node = qu.get() if node.left != None: qu.put( node.left ) if node.right != None: qu.put( node.right ) #print() def DFS(self): stack = [ [self.root, 0] ] # (node, no of visits) while stack != []: self.displayMarked( [item[0] for item in stack] , '*') node, nodeVisits = stack[-1] # stack top print( " in node ", node.key ) if nodeVisits == 0: stack[-1][1] += 1 # incr no. of visits if node.left != None: stack.append( [node.left, 0] ) # push continue if nodeVisits == 1: stack[-1][1] += 1 # incr no. of visits if node.right != None: stack.append( [node.right, 0] ) # push continue if nodeVisits == 2: stack.pop() # here, the stack does not contain the path from the root to the node def DFS9(self): stack = [ self.root ] # (node, no of visits) while stack != []: self.displayMarked( stack, '*') node = stack.pop() # stack pop print( " in node ", node.key ) if node.right != None: stack.append( node.right ) # push if node.left != None: stack.append( node.left ) # push # https://xlinux.nist.gov/dads/ # seed 1025 depth 3 38 3 random.seed( 1038 ) t = BinaryTree( 0 ) print( " rnd tree 2 " ) t.rndTree( t.root, 4 ) print( "set x coord" ) t.setXcoord(t.root, 0) print( "Display ") t.display() print( "BFS plain" ) t.BFS() print( "BFS2" ) t.BFS2() #exit() print( "Inorder " ) t.processInOrder(t.root) print( "Preorder " ) t.processPreOrder(t.root) print( "Inorder " ) t.processInOrder(t.root) print( "\n depth 2 ") t.root.depth = t.depth2( t.root ) print( "BFS2" ) t.BFS2() print( "DFS" ) t.DFS() print( "DFS9" ) t.DFS9()