SICP - 随笔分类 - R4mble

摘要：递归写法: 迭代写法: 阅读全文

posted @ 2018-01-31 23:56 R4mble 阅读(181) 评论(0) 推荐(0)

摘要：(define (compose f g) (lambda (x) (f (g x)))) ((compose square inc) 6) ((compose inc inc) 6) 阅读全文

posted @ 2018-01-31 23:54 R4mble 阅读(181) 评论(0) 推荐(0)

摘要：(define (double f) (lambda (x) (f (f x)))) (define (inc x) (+ x 1)) (((double (double double)) inc) 5) ;amazing (((double (double (double double))) inc) 0) 阅读全文

posted @ 2018-01-31 23:20 R4mble 阅读(147) 评论(0) 推荐(0)

2.2(点,线段,矩形的构造)

摘要：;2.2 (define (make-point x y) (cons x y)) (define (x-point p) (car p)) (define (y-point p) (cdr p)) (define (print-point p) (newline) (display "{") (display (x-point p)) (display ","... 阅读全文

posted @ 2018-01-31 22:44 R4mble 阅读(164) 评论(0) 推荐(0)

2.1(构造序对)

摘要：(define (make-rat n d) (let ((g (gcd n d))) (cons (/ n g) (/ d g)))) (define (numer x) (car x)) (define (denom x) (cdr x)) (define (print-rat x) (newline) (cond ((= (denom x) 1) (display ... 阅读全文

posted @ 2018-01-31 21:43 R4mble 阅读(154) 评论(0) 推荐(0)

let应用找零点

摘要：(define (search f neg-point pos-point) (let ((midpoint (average neg-point pos-point))) (if (close-enough? neg-point pos-point) midpoint (let ((test-value (f midpoint))) ... 阅读全文

posted @ 2017-11-25 03:13 R4mble 阅读(275) 评论(0) 推荐(0)

1.3.2 let

摘要：let赋值域变量不能从另一个获得阅读全文

posted @ 2017-11-25 02:21 R4mble 阅读(153) 评论(0) 推荐(0)

1.33 (累积互素数)

摘要：(define (filtered-accumulate filter? combiner null-value term a next b) (define (iter a result) (cond ((> a b) result) ((filter? a) (iter (next a) (combiner (... 阅读全文

posted @ 2017-11-25 01:57 R4mble 阅读(245) 评论(0) 推荐(0)

1.33 (过滤累积和求区间内所有素数之和)

摘要：(define (filtered-accumulate filter? combiner null-value term a next b) (define (iter a result) (cond ((> a b) result) ((filter? a) (iter (next a) (combiner (... 阅读全文

posted @ 2017-11-25 01:41 R4mble 阅读(359) 评论(0) 推荐(0)

1.32 (更高层次的抽象! 乘法与加法本来就是一回事)

摘要：(define (accumulate combiner null-value term a next b) (define (iter a result) (if (> a b) result (iter (next a) (combiner (term a) result)))) (iter a null-value)) (def... 阅读全文

posted @ 2017-11-25 01:10 R4mble 阅读(287) 评论(0) 推荐(0)

1.31 (另一种求圆周率的算法)

摘要：(define (product term a next b) (if (> a b) 1 (* (term a) (product term (next a) next b)))) (product (lambda (x) x) 1 (lambda (i) (+ i 1)) 5) ... 阅读全文

posted @ 2017-11-25 00:59 R4mble 阅读(236) 评论(0) 推荐(0)

1.30 (递归的sum变迭代)

摘要：为什么要把iter塞到sum里面去: 嗯,为了减少通信开销. 回头看递归写法: "我们要以困难的方式搞定它!" 阅读全文

posted @ 2017-11-24 23:37 R4mble 阅读(203) 评论(0) 推荐(0)

习题1.29 (积分方法的优化---simpson规则)

摘要：(define (sum term a next b) (if (> a b) 0 (+ (term a) (sum term (next a) next b)))) (define (integral f a b dx) ;积分 (define (add-dx x) (+ x dx)) (* (sum f (+ a (/ dx 2.0)... 阅读全文

posted @ 2017-11-24 23:26 R4mble 阅读(190) 评论(0) 推荐(0)

1.3.1 (对过程的抽象)

摘要：对过程的抽象: 填充: 拓展: 阅读全文

posted @ 2017-11-24 23:02 R4mble 阅读(144) 评论(0) 推荐(0)

SICP习题 1.23(素数查找的去偶数优化)

摘要：(define (next n) (if (= n 2) 3 (+ n 2))) (define (find-divisor n test-divisor) (cond ((> (square test-divisor) n) n) ((divides? n test-divisor) test-divisor) (else (f... 阅读全文

posted @ 2017-11-24 22:00 R4mble 阅读(212) 评论(0) 推荐(0)

SICP习题 1.22(素数)

摘要：(define (next-odd n) (if (odd? n) (+ 2 n) (+ 1 n))) (define (smallest-divisor n) (find-divisor n 2)) (define (find-divisor n test-divisor) (cond ((> (square test-divisor) n) n) ... 阅读全文

posted @ 2017-11-24 21:45 R4mble 阅读(236) 评论(0) 推荐(0)

SCIP习题 1.21(寻找最小因子)

摘要：19919997 阅读全文

posted @ 2017-11-24 21:07 R4mble 阅读(225) 评论(0) 推荐(0)

SICP 实例 1.2.6 素数寻找因子

摘要：如果N是合数,则必有一个小于或者等于根号N的素因子. 因为任何合数都可表示为两个或者更多个素数之积. 假如N是合数且其素因子都大于根号N,那么将产生矛盾:根号N*根号N>N.所以合数必有(至少)一个不大于根号N的素因子阅读全文

posted @ 2017-11-24 13:29 R4mble 阅读(168) 评论(0) 推荐(0)

SICP习题 1.19(对数级?---斐波那契数的再一次优化!!!)

摘要：用java来跑一跑: 经过我拙劣的比较,对数级比线性还是要好很多的. 阅读全文

posted @ 2017-11-24 12:01 R4mble 阅读(203) 评论(0) 推荐(0)

SICP习题 1.18 (对求乘积进行优化)

摘要：(define (double a) (+ a a)) (define (halve a) (/ a 2)) (define (mult a b) (mult-iter a b 0)) (define (mult-iter a b product) (cond ((= b 0) product) ((even? b) (mult-iter (double a... 阅读全文

posted @ 2017-11-24 11:39 R4mble 阅读(132) 评论(0) 推荐(0)

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