AoC 2025 day 2, part 2 (dc)

# Command: tr -c '0-9' ' ' <input | dc -fdc-p2.dc

[ q ] sQ

[
    # Note that hash is offset from start of range, so that indices are < 2^31 (max)
    d dls-;h 1r-*           # (1-hash(num-stat))*num num i
    lc+ sc                  # Score if not in hash
    dls- 1 r:h              # Record num in hash
] sC

?                           # end start ...
[
    se ss

    0 Sh                    # Clear hash

    1                       # i=1 ...
    [
        dddZAr^ dsf *+      # factor = 10^len(i); num=i,i i ...
        d le <Q             # quit search if two repeats is too large

        [
            d le <Q         # quit if (end < num)
            d ls !>C        # count if (num >= start)

            lf* r d3R+      # num = num,i
            lAx
        ] dsAx

        s. 1+ lLx           # junk num; i++ loop
    ] dsLx +s.

    z0<M
] dsMx

[Part 2: ]nlcp