二叉树问题---打印二叉树的边界节点

问题：
给定一棵二叉树的头节点，按照如下两种标准分别实现二叉树边界节点的逆时针打印。

标准一：

1.头节点为边界节点2.叶节点为边界节点3.如果节点在其所在层中的最左边或最右边，那么也是边界节点

标准二：

1.头节点为边界节点2.叶节点为边界节点3.树左边界延伸下去的路径为边界节点4.树右边界延伸下去的路径为边界节点

#标准一def printEdge1(root):    def getHeight(root, height=0):        if not root:            return 0        return max(getHeight(root.left, height+1), getHeight(root.right, height+1)) + 1    def getMap(root, i, map):        if not root:            return        if map[i][0] == None:            map[i][0] = root        map[i][1] = root        getMap(root.left, i+1, map)        getMap(root.right, i+1, map)    def printLeafNotInMap(root, i, map):        if not root:            return        if not root.left and not root.right and root != map[i][0] and \                root != map[i][1]:            print(root.val, end=' ')        printLeafNotInMap(root.left, i+1, map)        printLeafNotInMap(root.right, i+1, map)    if not root:        return    height = getHeight(root)    map = [[None for i in range(2)] for j in range(height)]    getMap(root, 0, map)    for i in range(len(map)):        print(map[i][0].val, end=' ')    printLeafNotInMap(root, 0, map)    for i in range(len(map)-1, -1, -1):        if map[i][0] != map[i][1]:            print(map[i][1].val, end=' ')#标准二def printEdge2(root):    def printLeft(root, isPrint):        if not root:            return        if isPrint or (root.left == None and root.right == None):            print(root.val, end=' ')        printLeft(root.left, isPrint)        printLeft(root.right, bool(isPrint and root.left == None))    def printRight(root, isPrint):        if not root:            return        printRight(root.left, bool(isPrint and root.right == None))        printRight(root.right, isPrint)        if isPrint or (root.left == None and root.right == None):            print(root.val, end=' ')    if not root:        return    print(root.val, end=' ')    if root.left and root.right:        printLeft(root.left, True)        printRight(root.right, True)    elif root.left:        printEdge2(root.left)    elif root.right:        printEdge2(root.right)