AoC 2025 day 6 part 2 (dc)

# Command: sed -e'$!s/ /0/g;$s/\(\S\)/[\1]/g' input | dc -fdc-p2.dc

0 ?                         # line i=0
[
    r d3R r:T               # Table(i) = line
    1+ ? z2=L
] dsLx

zR sn                       # numLines=i; op1 op2 op3 ...
z  so                       # numOpts

[ SO z0<L ] dsLx            # store ops on temp O stack
lo [ LO S* 1- d0<L ] dsLx   # reverse stack onto * stack

# stack: 0

# Process digit: digit i acc -> 0 i acc
[
    3R A*+                  # acc*10+digit i
    r0
] sP

[3Q] sQ

# Get next number: 0 -> acc
[
    0d                      # i=0 acc=0
    [
        d;T                 # Table(i) i acc
        A~                  # lastDigit rest i acc
        3Rd 4R r:T          # Table(i) = rest; i lastDigit i acc
        r d0<P              # 0 i acc
        +                   # clear 0
        1+ dln>I
    ] dsIx s.
    d0=Q                    # Force calling loop to quit if 0
] sN

# stack: sum=0 (still)

[
    lNx                     # get a number; num1 sum
    [
        lNx                 # num acc sum
        l*x                 # acc := acc op num
        lLx
    ] dsLx +
    +                       # sum += acc
    L*s.                    # pop op and junk
    lMx
] dsMx

[Part 2: ]n +p