Problem Statement

Two or more words are said to be anagrams if they have the same characters, but in a different order. By analogy with derangements we define a deranged anagram as two words with the same characters, but in which the same character does not appear in the same position in both words. Use the word list at unixdict to find and display the longest deranged anagram.

Let's start with the solution:

   #words=: 'b' freads 'unixdict.txt'
25104
   #anagrams=: (#~ 1 < #@>) (</.~ /:~&>) words
1303
   #maybederanged=: (#~ (1 -.@e. #@~."1)@|:@:>&>) anagrams
432
   #longest=: (#~ [: (= >./) #@>@{.@>) maybederanged
1
   longest
┌───────────────────────┐
│┌──────────┬──────────┐│
││excitation│intoxicate││
│└──────────┴──────────┘│
└───────────────────────┘