ps (material for lambda): Exercise 5.9.5: Define a recursive function reverse in

Question

ps (material for lambda):

Exercise 5.9.5: Define a recursive function reverse in Scheme which accepts only an S-list s as an argument and reverses the elements of s in linear time (i.e., time directly proportional to the size of s), O(n). You may use only define, lambda, let, cond, null?, cons, car, and cdr in reverse. You may not use append or letrec in your solution. 194 CHAPTER 5. FuNCTIONAL PROGRAMMING IN SCHEME Examples: 1 reverse (1 2 3 4 5 2 (5 4 3 2 1) 3 reverse (1)) 4 (1) 5 reverse (2 1) 6 (1 2) 7 reverse nite and day 8 (day and night) 9 reverse (1 (2 (3 (4 5))) 10 ((4 5) (2 (3)) 1)

Explanation / Answer

>>> def reversed_words(sequence):
...     return ' '.join(reversed(sequence.split()))
...
>>> reversed_words(s)
'23 12'
>>> s = "Heelo Gun Man"
>>> reversed_words(s)
'Man Gun Heelo'
>>>

Related Questions

Navigate

• Browse (All)
• Browse P
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.