Re: Challenge 3 The Runner-Up

[mnolan]

Indexing into the descending sorted list of distinct scores works pretty well ok

 

q)f:{desc[distinct x]1}
q)l:4 7 9 7 2 8 9
q)f[l]
8

 

EDIT: type and scale can matter here when looking for the best option. A version of the original suggestion outperforms mine in a lot of cases

q)f1:{max x except max x}  // original suggested solution
q)f2:{desc[distinct x]1}

q)l:4 7 9 7 2 8 9
q)t:10000 f1 l
9
q)t:10000 f2 l
16

q)longs:100000?100  //scale up
q)t:100 f1 longs
38
q)t:100 f2 longs  //lots of duplicates gives the “distinct” solution an advantage
19

q)floats:100000?100f  // change type to float
q)t:100 f1 floats
392
q)t:100 f2 floats  //advantage disappears when there are few duplicate entries
707