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https://github.com/Threnklyn/advent-of-code-go.git
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2018-day21: super confusing intcode solving
This commit is contained in:
alexchao26
@@ -0,0 +1,217 @@
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package main
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import (
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"flag"
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"fmt"
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"strings"
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"github.com/alexchao26/advent-of-code-go/util"
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)
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func main() {
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var part int
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flag.IntVar(&part, "part", 1, "part 1 or 2")
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flag.Parse()
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fmt.Println("Running part", part)
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if part == 1 {
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ans := part1(util.ReadFile("./input.txt"))
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fmt.Println("Output:", ans)
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} else {
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ans := part2(util.ReadFile("./input.txt"))
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fmt.Println("Output:", ans)
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}
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}
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func part1(input string) int {
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opcodeComputer := parseInput(input)
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for !opcodeComputer.tick() {
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// instruction 28 of my input is the only one that accesses register zero
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// it is comparing reg 0 to reg 5. so to break out of loops asap, set
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// reg 0 to the value found in reg 5 when 28 is hit for the first time
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if opcodeComputer.registers[opcodeComputer.instructionPointer] == 28 {
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break
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}
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}
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return opcodeComputer.registers[5]
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}
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func part2(input string) int {
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opcodeComputer := parseInput(input)
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// similar idea for part 2 but now we need to find the previous state of
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// register 5 when register 5 REPEATS itself. this is a brute force solution
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// using a map to store previous reg5 values, and stores the previous reg5
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var lastReg5 int
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comparedRegister5s := map[int]bool{}
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for !opcodeComputer.tick() {
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if opcodeComputer.registers[opcodeComputer.instructionPointer] == 28 {
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reg5 := opcodeComputer.registers[5]
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if comparedRegister5s[reg5] {
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break
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}
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comparedRegister5s[reg5] = true
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lastReg5 = reg5
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}
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}
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return lastReg5
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}
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type opcodeComputer struct {
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instructions []instruction
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registers [6]int
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instructionPointer int // an index the stores the index for which instruction to run
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}
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type instruction struct {
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name string
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abcValues [3]int
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}
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// literal opcode computer implementation, unoptimized
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func (o *opcodeComputer) tick() (done bool) {
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if o.registers[o.instructionPointer] >= len(o.instructions) {
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fmt.Println("Out of range instruction, terminating...")
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return true
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}
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instIndex := o.registers[o.instructionPointer]
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inst := o.instructions[instIndex]
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// fmt.Println(strings.Repeat(" ", instIndex) + strconv.Itoa(instIndex))
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opcodeFunc := opcodeNamesToFuncs[inst.name]
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o.registers = opcodeFunc(o.registers, inst.abcValues)
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// increment value @ instructionPointer, validate that it's still in range
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o.registers[o.instructionPointer]++
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if o.registers[o.instructionPointer] >= len(o.instructions) {
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return true
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}
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return false
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}
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func parseInput(input string) opcodeComputer {
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lines := strings.Split(input, "\n")
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var instructionPointer int
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fmt.Sscanf(lines[0], "#ip %d", &instructionPointer)
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var instructions []instruction
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for _, l := range lines[1:] {
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var inst instruction
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fmt.Sscanf(l, "%4s %d %d %d", &inst.name, &inst.abcValues[0], &inst.abcValues[1], &inst.abcValues[2])
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instructions = append(instructions, inst)
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}
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return opcodeComputer{
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instructions: instructions,
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instructionPointer: instructionPointer,
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}
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}
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var opcodeNamesToFuncs = map[string]opcodeFunc{
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"addr": addr, "addi": addi,
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"mulr": mulr, "muli": muli,
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"banr": banr, "bani": bani,
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"borr": borr, "bori": bori,
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"setr": setr, "seti": seti,
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"gtir": gtir, "gtri": gtri, "gtrr": gtrr,
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"eqir": eqir, "eqri": eqri, "eqrr": eqrr,
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}
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type opcodeFunc func([6]int, [3]int) [6]int
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func addr(registers [6]int, abcValues [3]int) [6]int {
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registers[abcValues[2]] = registers[abcValues[0]] + registers[abcValues[1]]
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return registers
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}
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func addi(registers [6]int, abcValues [3]int) [6]int {
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registers[abcValues[2]] = registers[abcValues[0]] + abcValues[1]
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return registers
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}
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func mulr(registers [6]int, abcValues [3]int) [6]int {
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registers[abcValues[2]] = registers[abcValues[0]] * registers[abcValues[1]]
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return registers
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}
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func muli(registers [6]int, abcValues [3]int) [6]int {
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registers[abcValues[2]] = registers[abcValues[0]] * abcValues[1]
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return registers
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}
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func banr(registers [6]int, abcValues [3]int) [6]int {
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registers[abcValues[2]] = registers[abcValues[0]] & registers[abcValues[1]]
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return registers
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}
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func bani(registers [6]int, abcValues [3]int) [6]int {
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registers[abcValues[2]] = registers[abcValues[0]] & abcValues[1]
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return registers
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}
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func borr(registers [6]int, abcValues [3]int) [6]int {
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registers[abcValues[2]] = registers[abcValues[0]] | registers[abcValues[1]]
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return registers
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}
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func bori(registers [6]int, abcValues [3]int) [6]int {
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registers[abcValues[2]] = registers[abcValues[0]] | abcValues[1]
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return registers
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}
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func setr(registers [6]int, abcValues [3]int) [6]int {
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registers[abcValues[2]] = registers[abcValues[0]]
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return registers
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}
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func seti(registers [6]int, abcValues [3]int) [6]int {
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registers[abcValues[2]] = abcValues[0]
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return registers
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}
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func gtir(registers [6]int, abcValues [3]int) [6]int {
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if abcValues[0] > registers[abcValues[1]] {
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registers[abcValues[2]] = 1
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} else {
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registers[abcValues[2]] = 0
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}
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return registers
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}
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func gtri(registers [6]int, abcValues [3]int) [6]int {
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if registers[abcValues[0]] > abcValues[1] {
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registers[abcValues[2]] = 1
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} else {
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registers[abcValues[2]] = 0
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}
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return registers
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}
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func gtrr(registers [6]int, abcValues [3]int) [6]int {
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if registers[abcValues[0]] > registers[abcValues[1]] {
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registers[abcValues[2]] = 1
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} else {
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registers[abcValues[2]] = 0
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}
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return registers
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}
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func eqir(registers [6]int, abcValues [3]int) [6]int {
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if abcValues[0] == registers[abcValues[1]] {
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registers[abcValues[2]] = 1
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} else {
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registers[abcValues[2]] = 0
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}
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return registers
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}
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func eqri(registers [6]int, abcValues [3]int) [6]int {
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if registers[abcValues[0]] == abcValues[1] {
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registers[abcValues[2]] = 1
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} else {
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registers[abcValues[2]] = 0
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}
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return registers
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}
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func eqrr(registers [6]int, abcValues [3]int) [6]int {
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if registers[abcValues[0]] == registers[abcValues[1]] {
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registers[abcValues[2]] = 1
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} else {
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registers[abcValues[2]] = 0
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}
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return registers
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}
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@@ -0,0 +1,41 @@
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package main
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import (
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"testing"
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"github.com/alexchao26/advent-of-code-go/util"
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)
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func Test_part1(t *testing.T) {
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tests := []struct {
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name string
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input string
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want int
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}{
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{"actual", util.ReadFile("input.txt"), 2884703},
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}
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for _, tt := range tests {
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t.Run(tt.name, func(t *testing.T) {
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if got := part1(tt.input); got != tt.want {
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t.Errorf("part1() = %v, want %v", got, tt.want)
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}
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})
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}
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}
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func Test_part2(t *testing.T) {
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tests := []struct {
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name string
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input string
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want int
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}{
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{"actual", util.ReadFile("input.txt"), 15400966},
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}
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for _, tt := range tests {
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t.Run(tt.name, func(t *testing.T) {
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if got := part2(tt.input); got != tt.want {
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t.Errorf("part2() = %v, want %v", got, tt.want)
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}
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})
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}
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}
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