From 8d5a356c8ee0f6c4f40ee40fd2b89ca248cc92c3 Mon Sep 17 00:00:00 2001 From: Jan Sucan Date: Sat, 11 Mar 2023 13:47:15 +0100 Subject: 3_b_4: Add solution --- ch03/3_b_4.hs | 15 +++++++++++++++ 1 file changed, 15 insertions(+) create mode 100644 ch03/3_b_4.hs (limited to 'ch03') diff --git a/ch03/3_b_4.hs b/ch03/3_b_4.hs new file mode 100644 index 0000000..a711085 --- /dev/null +++ b/ch03/3_b_4.hs @@ -0,0 +1,15 @@ +-- Turn a list into a palindrome, i.e. it should read the same both backwards +-- and forwards. For example, given the list [1,2,3], your function should +-- return [1,2,3,3,2,1]. + +makePalindrome :: [a] -> [a] +makePalindrome [] = [] +makePalindrome (x:xs) = [x] ++ (makePalindrome xs) ++ [x] + +-- ghci> :l 3_b_4.hs +-- [1 of 1] Compiling Main ( 3_b_4.hs, interpreted ) +-- Ok, one module loaded. +-- ghci> makePalindrome [] +-- [] +-- ghci> makePalindrome [1, 2, 3] +-- [1,2,3,3,2,1] -- cgit v1.2.3