MappedIndices ← +⊃(\+×≡/×=@.)(⇡⧻): -1

Input ← &fras "../day_11.txt"
⊜∘≠, @\n Input                       # split on newlines
↯¯1_2⊞⊂ ∩(MappedIndices 1000000) ⊃∘⍉ # map indices
=@#▽≠@\n. Input                      # find galaxies
▽                                    # keep galaxies
↯¯1_2_2⊠⊟.                           # galaxy pairs
/+≡(/+⌵-°⊟)                          # distances
÷2                                   # account for reversed pairs