think2times

摘要： Exercise 2.41 Write a procedure to find all ordered triples of distinct positive integers i, j, and k less than or equal to a given integer n that sum 阅读全文

摘要： Exercise2.40 Define a procedure unique-pairs that, given an integer n, generates the sequence of pairs (i, j) with 1 < j < i < n. Use unique-pairs to 阅读全文

摘要： Exercise 2.38 The accumulate procedure is also known as fold-right, because it combines the first element of the sequence with the result of combining 阅读全文

摘要： 果然习惯不能停，就两天没学，昨天就忘的干干净净了。。今天把昨天的补上 Exercise 2.36 The procedure accumulate-n is similar to accumulate except that it takes as its third argument a sequ 阅读全文

摘要： 十一去喀纳斯玩了2天，今天恢复，才几天没看书再看到代码就感到有点陌生了。。 Exercise 2.35 Redefine count-leaves from Section 2.2.2 as an accumulation: (define (count-leaves t) (accumulate 阅读全文

摘要： Exercise 2.34 Evaluating a polynomial in x at a given value of x can be formulated as an accumulation. We evaluate the polynomial an x^n + a{n-1} x^(n 阅读全文

摘要： Exercise 2.33 Fill in the missing expressions to complete the following definitions of some basic list-manipulation operations as accumulations: ; p 表 阅读全文

摘要： 上一道题没什么改动，再来一道 Exercise 2.32 We can represent a set as a list of distinct elements, and we can represent the set of all subsets of the set as a list o 阅读全文

摘要： Exercise 2.31 Abstract your answer to Exercise 2.30 to produce a procedure $tree-map$ with the property that $square-tree$ could be defined as (define 阅读全文

摘要： Exercise 2.30 Define a procedure square-tree analogous to the square-list procedure of Exercise 2.21. That is, square-tree should behave as follows: ( 阅读全文