Difference between revisions of "Nhc98"
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(Here is a program to form a new list from two given lists such that a term appears in this new list iff it appeared in exactly one of those two lists. It takes O(nlog n) time.) |
(No difference)
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Revision as of 10:57, 12 August 2012
uncommon :: [Int]->[Int]->[Int] uncommon x y=common (finalsort (x++y))
common :: [Int]->[Int] common []=[] common [x]=[x] common (x:y:zs)
| (x==y) =common zs | otherwise =x:(common (y:zs))
sort :: [Int]->[Int]->[Int] sort [] x=x sort x []=x sort (x:xs) (y:ys)
| (x>=y) =x:(sort xs (y:ys)) | otherwise =y:(sort (x:xs) ys)
finalsort :: [Int]->[Int] finalsort [x]=[x] finalsort x=sort (finalsort (first x)) (finalsort (lastest x))
mylength :: [Int]->Int mylength []=0 mylength (x:xs)=1+ mylength xs
auxfirst :: [Int]->Int->[Int] auxfirst x 0=[] auxfirst (y:ys) x=y:(auxfirst ys (x-1))
first :: [Int]->[Int] first x=auxfirst x (div (mylength x) 2)
auxlast :: [Int]->Int->[Int] auxlast x 0=x auxlast (x:xs) y=auxlast xs (y-1)
lastest :: [Int]->[Int] lastest x=auxlast x (div (mylength x) 2)