Given a binary tree, return thepostordertraversal of its nodes’ values.
For example:Given binary tree{1,#,2,3},
1\2/ 3
return[3,2,1].
Note:Recursive solution is trivial, could you do it iteratively?
# Definition for a binary tree node# class TreeNode#attr_accessor :val, :left, :right#def initialize(val)#@val = val#@left, @right = nil, nil#end# end# @param {TreeNode} root# @return {Integer[]}def postorder_traversal(root)stack = [[false, root]]ans = []while not stack.empty?f, n = stack.pop()if nif not fstack << [true, n] << [false, n.right] << [false, n.left]elseans << n.valendendendansend
，不要因为世态变迁而埋怨,不要因为命运多舛而怨恨.
