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; HW03.lisp - Homework Assignment #3 for CS408, Fall Quarter, 2006
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; Copyright (c) 2006 Ira W. Snyder (devel@irasnyder.com)
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;
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; Permission is hereby granted, free of charge, to any person obtaining a copy
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; of this software and associated documentation files (the "Software"), to deal
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; in the Software without restriction, including without limitation the rights
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; to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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; copies of the Software, and to permit persons to whom the Software is
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; furnished to do so, subject to the following conditions:
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;
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; The above copyright notice and this permission notice shall be included in all
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; copies or substantial portions of the Software.
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;
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; THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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; IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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; FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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; AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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; LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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; OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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; SOFTWARE.
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;;; Problem 1
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(defun PALINDROME (LI)
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(append LI (reverse LI))
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)
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;;; Problem 2
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; Tail-recursive helper for problem 2
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(defun PALINDROMEP1 (L1 L2)
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(cond
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((null L1) t)
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((equal (car L1) (car L2)) (PALINDROMEP1 (cdr L1) (cdr L2)))
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(t nil)
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)
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)
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(defun PALINDROMEP (LI)
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(PALINDROMEP1 LI (reverse LI))
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)
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;;; Problem 3
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(defun DIVISIBLE-BY-N (DIVIDEND DIVISOR)
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(cond
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((= (mod DIVIDEND DIVISOR) 0) t)
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(t nil)
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)
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)
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;;; Problem 4
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(defun SQUASH (LI)
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(cond
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((null LI) nil)
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((atom LI) (list LI))
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(t (append (SQUASH (car LI)) (SQUASH (cdr LI))))
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)
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)
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;;; Problem 5
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(defun COUNT-ATOMS (LI)
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(cond
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((null LI) 0)
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((atom LI) 1)
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(t (+ (COUNT-ATOMS (car LI)) (COUNT-ATOMS (cdr LI))))
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)
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)
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; vim: set ts=2 sts=2 sw=2 expandtab textwidth=80:
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