NB. happy dinner http://adventofcode.com/day/13

m=: ' '&cut & > cutLF ('.',CR) -.~ fread {:ARGV NB. matrix of input
u=: ~. {."1 m                NB. noun: unique names = all the ppl
s=: _1 1{~'gain'-: >@:(2&{)  NB. _1 for 'lose', 1 for 'gain'
n=: ". @ > @ (3&{)           NB. numeric value
g=: 4 : 'v=.0$~2##x for_e. y do. v=. ((s*n)e) (< x i. 0 10{e) }v end. v' NB. calc matrix
v=: u g m                    NB. noun: 'happiness' matrix; all data are parsed now

h=: {&v @ < @ ,              NB. get 'happiness' for x -> y
r=: 2 h/\ ]                  NB. one way relations between ppl in one combination
w=: +/@r + +/@r@|.           NB. total happiness of one combination
p=: ([ , {.)"1@(i.@! A. i.)  NB. all permutation with first column appended on the right
echo >./ w"1 p #u

h=: ({&v @ < @ ,) :: 0:      NB. all missing 'happiness' values will be 0
echo >./ w"1 p >:#u          NB. repeat calculation for one more (virtual) person

exit 0