SignalChapter 8: Scarcity

61SHORT HAND

The task

P must receive the sum of each group of 4 values from X. A part group at the end is dropped.

w1 and w2 are standard cores cut to 4 lines. n1 and n2 are SC-1s: register A only, 8 lines.

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 core's own lines cuts an SC-2 to 4, too few to add a pair; IN, XCH, ADD B, OUT adds neighbors and an SC-1 keeps every second sum.

Hints

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

Hint 1Show

A core can hold fewer lines than its model, and 4 lines are too few to add a pair.

Hint 2Show

IN, XCH, ADD B, OUT adds each value to the one before it. Every second sum is a pair.

Hint 3Show

An SC-1 that reads twice and writes once keeps every second value.

Solution

Reveal the Full SolutionThe complete program for SHORT HAND. 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.

w1SC-2 standard

IN P0
XCH A, B
ADD B
OUT P1

n1SC-1 lite

IN P0
IN P0
OUT P1

w2SC-2 standard

IN P0
XCH A, B
ADD B
OUT P1

n2SC-1 lite

IN P0
IN P0
OUT P1

CYCLES: 189; at par
ENERGY: 1584; at par
NODES: 4; at par
INSTRUCTIONS: 14; at par