SignalChapter 10: Meshes

77SPOKES

The task

P must receive 2 times X cubed, minus 3 times X squared, minus 11 times X, plus 6.

s1, s2, and s3 are SC-2Ls: 2 cycles an instruction, at half the energy.

Each spoke has one two way wire to h: a job goes out on it and the answer comes back.

The board

The board as the puzzle screen lays it out. Cyan pins read, lemon pins write, violet pins go both ways. On a narrow screen, scroll the board sideways to see all of it.

Key idea

A hub on two way spokes sends a job down every spoke before it waits for any answer.

Hints

Each hint goes a step further than the one before. Open them one at a time.

Hint 1Show

Send a job down every spoke before you wait for any answer.

Hint 2Show

Read each answer before you send that spoke its next job, or the wire is HEAD ON.

Hint 3Show

Work from the inside out: 2X minus 3, times X, minus 11, times X, plus 6.

Solution

Reveal the Full SolutionThe complete program for SPOKES. Open it only when you want the answer.

The reference program

The game's own solution. It passes every test and scores exactly par on every benchmark.

hSC-2 standard

IN P0
OUT P1
IN P0
OUT P2
IN P0
OUT P3
IN P1
OUT P4
IN P2
OUT P4
IN P3
OUT P4

s1SC-2L low power

IN P0
MOV B, A
MUL 2
SUB 3
MUL B
SUB 11
MUL B
ADD 6
OUT P0

s2SC-2L low power

IN P0
MOV B, A
MUL 2
SUB 3
MUL B
SUB 11
MUL B
ADD 6
OUT P0

s3SC-2L low power

IN P0
MOV B, A
MUL 2
SUB 3
MUL B
SUB 11
MUL B
ADD 6
OUT P0

CYCLES: 365; at par
ENERGY: 1989; at par
NODES: 4; at par
INSTRUCTIONS: 39; at par

Another way: Alone

A second program that also passes. It beats par on NODES and INSTRUCTIONS and gives some back on CYCLES and ENERGY.

H works out every value itself: one core and 9 lines, but h spends 2 energy an instruction and still falls behind the three spokes.

hSC-2 standard

IN P0
MOV B, A
MUL 2
SUB 3
MUL B
SUB 11
MUL B
ADD 6
OUT P4

CYCLES: 391; over par
ENERGY: 2106; over par
NODES: 1; under par
INSTRUCTIONS: 9; under par