Structure and Interpretation of Computer Programs (SICP) is a classic textbook for learning how to program. The language used in the book is Scheme, a dialect of Lisp.
0
votes
1answer
26 views
Reverse the order of a list in Racket
I am using the SICP book. There is an exercise in which you need to create a function that will receive a list as an argument and return a list with the same elements in a reverse order.
I know there ...
2
votes
1answer
58 views
Church Numerals
Here is exercise 2.6 from SICP:
Exercise 2.6: In case representing pairs as procedures wasn’t
mind-boggling enough, consider that, in a language that can manipulate
procedures, we can get by ...
3
votes
1answer
89 views
SICP exercise 1.28 - miller-rabin primality test part II
This is a follow-up to SICP exercise 1.28 - miller-rabin primality test.
Exercise 1.28:
One variant of the Fermat test that cannot be fooled is
called the Miller-Rabin test (Miller 1976; ...
2
votes
1answer
111 views
SICP exercise 1.28 - miller-rabin primality test
From SICP
Exercise 1.28:
One variant of the Fermat test that cannot be fooled is
called the Miller-Rabin test (Miller 1976; Rabin 1980). This starts
from an alternate form of Fermat’s ...
2
votes
1answer
26 views
SICP 1.3 Sum of Squares of two largest numbers
Define a procedure that takes three numbers as arguments and returns the sum of squares of the two largest numbers.
I'm using just the machinery that was developed so far in SICP to be true to the ...
1
vote
1answer
48 views
SICP - exercise 1.12 - pascal's triangle
From SICP:
Exercise 1.12: The following pattern of numbers is called Pascal’s triangle.
1
1 1
1 2 1
1 3 3 1
1 4 6 4 1
. . .
The numbers at the ...
3
votes
1answer
56 views
SICP - exercise 1.11 - tree recursion
From SICP
Exercise 1.11: A function \$f\$ is defined by the rule that:
\$f(n) = n\$ if \$n < 3\$, and
\$f(n) = f(n-1)+2f(n-2)+3f(n-3)\$ if \$n >= 3\$.
Write a procedure ...
3
votes
1answer
50 views
Square root calculation in Scheme (SICP Exercise 1.7)
I have done exercise 1.7 in SICP (calculate square root precision when change in guesses is under a certain value), but I am calling the change-in-precision function twice in each iteration, which ...
2
votes
1answer
53 views
SICP exercise 1.3 - sum of squares of two largest of three numbers
From SICP
Exercise 1.3: Define a procedure that takes three numbers as arguments and returns the sum of the squares of the two larger numbers.
Square is:
...
4
votes
1answer
74 views
SICP - exercise 2.69 - generate a huffman tree from a set of ordered leaves
From SICP
Exercise 2.69: The following procedure takes as its argument a list of
symbol-frequency pairs (where no symbol appears in more than one pair)
and generates a Huffman encoding tree ...
3
votes
1answer
57 views
SICP exercise 2.28 - counting leaves in a tree (recursive process)
From SICP
Exercise 2.28: Write a procedure fringe that takes as argument a tree
(represented as a list) and returns a list whose elements are all the
leaves of the tree arranged in left-to-...
2
votes
2answers
73 views
SICP - exercise 2.27 - reversing elements of a list and sublists
From SICP
Exercise 2.27: Modify your deep-reverse procedure of Exercise 2.18 to produce a deep-deep-reverse procedure that takes a list as argument and returns as its value the list with its ...
1
vote
1answer
48 views
SICP - exercise 2.5 - representing pairs of nonnegative integers using only numbers and arithmetic operations
From SICP
Exercise 2.5: Show that we can represent pairs of nonnegative integers using only numbers and arithmetic operations if we represent the pair a and b as the integer that is the product 2^x*3^...
2
votes
1answer
25 views
Replacing elements from a list and its sublists - part II
This is sort of a follow-up to
Replacing elements from a list and its sublists
but now there are arbitrary numbers of words that would be replaced stored in a list.
Now write substitute2 that takes ...
1
vote
2answers
48 views
SICP - exercise 2.20 - same-parity
Exercise 2.20.
The procedures +, *, and list take arbitrary numbers of arguments. One way to define such procedures is to use define with dotted-tail notation. In a procedure
definition, a parameter ...
3
votes
1answer
71 views
Reversing a list without (append)
I would like to reverse a list using cdr, car and cons. Since lists in lisp are asymmetrical (can only insert at the beginning), I am interested on how one would write a procedure to do that without ...
3
votes
1answer
60 views
Replacing elements from a list and its sublists
Write a procedure substitute that takes three arguments: a list, an old word, and a new word. It should return a copy of the list, but with every occurrence of the old word replaced by the new word, ...
5
votes
1answer
62 views
Finding next perfect number - brute force
A “perfect number” is defined as a number equal to the sum of all its factors less than itself. For example, the first perfect number is 6, because its factors are 1, 2, 3, and 6, and 1+2+3=6. The ...
4
votes
2answers
95 views
Squaring a tree in Clojure
I am working on Problem 2.30 from Structure and Interpretation of Computer Programs. I book is in scheme, but I am doing the exercises in Clojure.
The problem is to write code that takes a tree of ...
3
votes
1answer
57 views
Replacing words from a sentence
I am extremely new at scheme and I am doing this problem from here:
Write a procedure switch that takes a sentence as its argument and
returns a sentence in which every instance of the words I or ...
5
votes
3answers
696 views
Recursive and iterative approach for mergesort
Problem:
Question 8: *
Mergesort is a type of sorting algorithm. It follows a naturally
recursive procedure:
Break the input list into equally-sized halves Recursively sort both ...
-1
votes
2answers
320 views
Filter a list with given predicate - python [closed]
For the following question, the function
• should mutate the original list
• should NOT create any new lists
• should NOT return anything
Function that do not create new lists are ...
2
votes
5answers
6k views
Shift elements left by n indices in a list
For the following question, the function
• should mutate the original list
• should NOT create any new lists
• should NOT return anything
Functions that do not create new lists are ...
0
votes
1answer
147 views
Interval multiplication - faster version
For the below given problem from this assignment:
Q4. In passing, Ben also cryptically comments, "By testing the signs of the endpoints of the intervals, it is possible to break ...
1
vote
1answer
318 views
Is there something wrong with my remove-duplicates implementation in Scheme?
For an assignment I handed in this code to remove duplicates from a stream.
...
3
votes
1answer
70 views
SICP Exercise 1.3: Sum of squares of two largest numbers out of three, Prolog Version
The exercise 1.3 of the book Structure and Interpretation of Computer Programs asks the following:
Exercise 1.3. Define a procedure that takes three numbers as arguments and returns the sum of the ...
3
votes
1answer
56 views
SICP Exercise 1.3: Sum of squares of two largest numbers out of three, Rust Version
The exercise 1.3 of the book Structure and Interpretation of Computer Programs asks the following:
Exercise 1.3. Define a procedure that takes three numbers as arguments and returns the sum of the ...
5
votes
1answer
136 views
SICP Exercise 1.3: Sum of squares of two largest numbers out of three, Haskell Version
The exercise 1.3 of the book Structure and Interpretation of Computer Programs asks the following:
Exercise 1.3. Define a procedure that takes three numbers as arguments and returns the sum of the ...
5
votes
3answers
340 views
SICP Exercise 1.3: Sum of squares of two largest numbers out of three
The exercise 1.3 of the book Structure and Interpretation of Computer Programs asks the following:
Exercise 1.3. Define a procedure that takes three numbers as arguments and returns the sum of the ...
3
votes
1answer
89 views
SICP streams in C++
To brush up on my C++ chops, I've implemented a toy version of "SICP Streams", which behave like lists with one twist: the first element of the list is always available, the rest of the list is stored ...
4
votes
0answers
122 views
Building Data abstraction and ADT for rectangle using “objects”
For the below given exercise:
Exercise 7: Abstracting Rectangles
Implement a representation for rectangles in a plane. (Hint: You may want to make use of your procedures from exercise 5). Then,...
4
votes
1answer
102 views
Encapsulated state in clojure
While going through SICP and trying to implement the code in clojure, I've found that while I can get the code in chapter 3 to work, it seems to go against Clojure idioms, but I can't quite imagine ...
3
votes
2answers
102 views
This snippet of scheme calculates a value in pascal's triangle
I'm working through SICP and have implemented exercise 1.11 (Pascal's Triangle). What I'm curious about here is performance considerations by defining functions within the main function. I would ...
7
votes
2answers
417 views
My first accumulators
Notes
I'm working my way through SICP, and as I got very confused by the section on folds, I decided to try to implement foldr in scheme and javascript to understand how it works differently with ...
1
vote
0answers
169 views
SICP ex. 2.42 “eight queens puzzle”
The problem can be found online here.
In short, we're given the following function definition, that will recursively generate all the possible solutions for the "eight-queen-problem".
...
7
votes
2answers
166 views
Write a procedure stream-limit that finds
From SICP:
Exercise 3.64. Write a procedure
stream-limit that takes as arguments a
stream and a number (the tolerance).
It should examine the stream until it
finds two successive elements ...
1
vote
0answers
161 views
Write a definition of a semaphore in terms of test-and-set! operations
From SICP:
Exercise 3.47. A semaphore (of size
n) is a generalization of a mutex.
Like a mutex, a semaphore supports
acquire and release operations, but it
is more general in that up to n
...
1
vote
0answers
175 views
Write a definition of a semaphore in terms of mutexes
From SICP:
Exercise 3.47. A semaphore (of size
n) is a generalization of a mutex.
Like a mutex, a semaphore supports
acquire and release operations, but it
is more general in that up to n
...
4
votes
0answers
158 views
Representing a queue as a procedure with local state
From SICP:
Exercise 3.22. Instead of
representing a queue as a pair of
pointers, we can build a queue as a
procedure with local state. The local
state will consist of pointers to the
...
5
votes
1answer
310 views
Examine a list for cycles
From SICP:
Exercise 3.18. Write a procedure that
examines a list and determines whether
it contains a cycle, that is, whether
a program that tried to find the end
of the list by taking ...
1
vote
0answers
470 views
Correctly count the number of pairs in an irregular list structure
From SICP:
For background, here is exercise 3.16:
Exercise 3.16
Ben Bitdiddle decides
to write a procedure to count the
number of pairs in any list structure.
...
2
votes
1answer
289 views
Order of evaluation of function arguments
From SICP:
Exercise 3.8
When we defined the
evaluation model in section 1.1.3, we
said that the first step in evaluating
an expression is to evaluate its
subexpressions. But we never ...
1
vote
0answers
161 views
Coercion of arguments using successive raising
From SICP:
Exercise 2.84
Using the raise
operation of exercise 2.83, modify the
apply-generic procedure so that it
coerces its arguments to have the same
type by the method of ...
1
vote
0answers
344 views
Coercion with multiple arguments
From SICP:
Exercise 2.82
Show how to generalize
apply-generic to handle coercion in
the general case of multiple
arguments. One strategy is to attempt
to coerce all the arguments to ...
3
votes
1answer
782 views
Huffman encoding successive-merge function
From SICP:
Exercise 2.69. The following
procedure takes as its argument a list
of symbol-frequency pairs (where no
symbol appears in more than one pair)
and generates a Huffman encoding ...
2
votes
1answer
904 views
Encode-symbol for Huffman tree
From the text:
Exercise 2.68. The encode procedure
takes as arguments a message and a
tree and produces the list of bits
that gives the encoded message.
...
3
votes
1answer
355 views
Search on a binary tree
From SICP:
Exercise 2.66. Implement the lookup
procedure for the case where the set
of records is structured as a binary
tree, ordered by the numerical values
of the keys.
I wrote the ...
2
votes
0answers
1k views
Union-set intersection-set for a binary-tree implementation of sets
From SICP:
Exercise 2.65
Use the results of
exercises 2.63 and 2.64 to give (n)
implementations of union-set and
intersection-set for sets implemented
as (balanced) binary trees.41
I ...
2
votes
1answer
359 views
Adjoin-set for an ordered set representation
From SICP:
Exercise 2.61
Give an implementation
of adjoin-set using the ordered
representation. By analogy with
element-of-set? show how to take
advantage of the ordering to produce a
...
4
votes
1answer
187 views
Set representation allowing duplicates
From SICP:
Exercise 2.60. We specified that a
set would be represented as a list
with no duplicates. Now suppose we
allow duplicates. For instance, the
set {1,2,3} could be represented as
...
