以一个题目来说明 (define (square x) (* x x)) (define (sum-squares x y) (+ (square x) (square y))) (define (f a) (sum-squares (+ a 1) (* a 2))) 列如求 (f 5) 应用序 应用序则是先一步步替换子组合求值再去应用的为应用序("evaluate the arguments and then apply"翻译为"先求参数值再应用") `(f 5)…
Exercise 1.5. Ben Bitdiddle has invented a test to determine whether the interpreterhe is faced with is using applicative-order evaluation or normal-orderevaluation. He defines the following two procedures: (define (p) (p)) (define (test x y) (if …
在Java语言学习中,通常不太关注求值规则. (2+4*6)*(3+5+7)这样的组合式的求值规则.通常归结为优先级问题: if.for等的求值规则通常归结为语义. 函数式编程语言的Scheme,将这些归结为求值规则.依照丘奇的λ演算的函数应用:A.B是λ表达式,则 (A B) 也是λ表达式.表示将实參B带入函数A中. 问题是:实參B带入函数A中时是否须要对实參B求值呢? applicative-order Vs.normal-order ''evaluate the arguments and…
3.1 排序数据 子句(clause) SQL语句由子句构成.一个子句通常由一个关键字加上所提供的数据组成. ORDER BY子句可以取一个或多个列的名字,将SELECT语句检索出的数据进行排序. ORDER BY子句可以使用非检索的列排序数据. ORDER BY子句必须作为SELECT语句中最后一条子句. MariaDB [sqlbzbh]> SELECT prod_name FROM Products ORDER BY prod_name; +---------------------+ |…
Description Once upon a time there was a greedy King who ordered his chief Architect to build a wall around the King's castle. The King was so greedy, that he would not listen to his Architect's proposals to build a beautiful brick wall with a perfec…
Given a binary search tree and a node in it, find the in-order successor of that node in the BST. Note: If the given node has no in-order successor in the tree, return null. 这道题让我们求二叉搜索树的某个节点的中序后继节点,那么我们根据BST的性质知道其中序遍历的结果是有序的, 是我最先用的方法是用迭代的中序遍历方法,然后用…
Given an array of numbers, verify whether it is the correct preorder traversal sequence of a binary search tree. You may assume each number in the sequence is unique. Follow up: Could you do it using only constant space complexity? 这道题让给了我们一个一维数组,让我们…
Given a binary tree, return the postorder traversal 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? 经典题目,求二叉树的后序遍历的非递归方法,跟前序,中序,层序一样都需要用到栈,后续的…
Given a binary tree, return the preorder traversal of its nodes' values. For example:Given binary tree {1,#,2,3}, 1 \ 2 / 3 return [1,2,3]. Note: Recursive solution is trivial, could you do it iteratively? 一般我们提到树的遍历,最常见的有先序遍历,中序遍历,后序遍历和层序遍历,它们用递归实现起…
Given inorder and postorder traversal of a tree, construct the binary tree. Note: You may assume that duplicates do not exist in the tree. 这道题要求从中序和后序遍历的结果来重建原二叉树,我们知道中序的遍历顺序是左-根-右,后序的顺序是左-右-根,对于这种树的重建一般都是采用递归来做,可参见我之前的一篇博客Convert Sorted Array to Bin…
Given preorder and inorder traversal of a tree, construct the binary tree. Note:You may assume that duplicates do not exist in the tree. 这道题要求用先序和中序遍历来建立二叉树,跟之前那道Construct Binary Tree from Inorder and Postorder Traversal 由中序和后序遍历建立二叉树原理基本相同,针对这道题,由于先…
Given a binary tree, return the inorder traversal of its nodes' values. For example:Given binary tree {1,#,2,3}, 1 \ 2 / 3 return [1,3,2]. Note: Recursive solution is trivial, could you do it iteratively? confused what "{1,#,2,3}" means? > re…
