a.vx

#!/usr/bin/env vx

const bindir = dirname realpath argv[ 0 ]

const input_path = if argc > 1 then {argv[ 1 ]} else {bindir "/input.txt"}

const data = (load input_path).lines()

var memory = [packed data / ','] map {int v.string}

var PC = 0

const opcodes = [ null, Math.sum, Math.product ]

def run (input)
{
	while true do
	{
		const opcode = memory[ PC++ ]
		
		const op = opcode % 100
		
		var modes = opcode div 100
		
		if op == 99 then
		{
			break
		}
		
		const i = memory[ PC++ ]
		const a = if modes % 10 then {i} else {memory[ i ]}
		
		if op == 3 then
		{
			memory[ i ] = input
			continue
		}
		
		if op == 4 then
		{
			print^+(a != 0) a
			continue
		}
		
		modes = modes div 10
		
		const j = memory[ PC++ ]
		const b = if modes % 10 then {j} else {memory[ j ]}
		
		const k = memory[ PC++ ]
		
		const c = opcodes[ op ]( a, b )
		
		memory[ k ] = c
	}
}

run 1