perm filename MIDTER.F75[206,LSP] blob sn#185965 filedate 1975-11-13 generic text, type C, neo UTF8

COMMENT ⊗ VALID 00002 PAGES C REC PAGE DESCRIPTION C00001 00001 C00002 00002 .device xgp C00005 ENDMK C⊗; .device xgp .font 1 "basl30" <<text>> .font 2 "bdr30" <<sym>> .font 3 "basi30" <<var>> .font 4 "basb30" <<bold>> .evenleftborder←oddleftborder←1100; .page frame 52 high 79 wide; .area text lines 1 to 51 chars 1 to 79; .place text; .TURN ON "←%"; .NOFILL ←COMPUTER SCIENCE DEPARTMENT ←STANFORD UNIVERSITY ←CS 206 COMPUTING WITH SYMBOLIC EXPRESSIONS FALL 1975 ←MIDTERM EXAM %1←Open Books and Notes .FILL Write LISP functions as follows using the M-expression notation used in class: .SKIP 2 1. %3foo u%1 is a list consisting of the atomic elements of the list %3u%1 followed by the non-atomic elements preserving order within each group. Thus %3foo%1[(A (B C) A B (D E))] = (A A B (B C) (D E))) 2. Let a polynomial in %3x%1 be represented by a list of its coefficients in order of ascending powers of %3x%1. Thus %3x%53%3+x+5%1 is represented by (5 1 0 1). %3prod(u,v)%1 gives the product of the polynomials %3u%1 and %3v%1 in the same notation. 3. %3commons u%1 is a list of the sublists of the list %3u%1 that occur more than once in %3u%1 each followed by a list of the locations where it occurs. The location of a sub expression is a list of A's and D's such that starting a the beginning of 4. %3locations%2[%3e,u%2]%1 is a list of the locations of the occurences of the expression %3e%1 as a subexpression of the expression %3u%1. A location is a list of A's and D's such that %3e%1 is reached by taking