Add solution for Day 7

Signed-off-by: Knut Ahlers <knut@ahlers.me>

day07.go

@@ -0,0 +1,102 @@
+package aoc2019
+
+import (
+	"io/ioutil"
+	"strings"
+
+	"github.com/pkg/errors"
+)
+
+func day07TestMaxOutputFromChain(code []int, chainStart, chainEnd int, looped bool) int {
+	var (
+		chainLen = chainEnd - chainStart + 1
+		permuts  [][]int
+		permute  func(a []int, k int)
+		rootSeq  = make([]int, chainLen)
+	)
+
+	permute = func(a []int, k int) {
+		if k == len(a) {
+			permuts = append(permuts, append([]int{}, a...))
+		} else {
+			for i := k; i < len(rootSeq); i++ {
+				a[k], a[i] = a[i], a[k]
+				permute(a, k+1)
+				a[k], a[i] = a[i], a[k]
+			}
+		}
+	}
+
+	for i := range rootSeq {
+		rootSeq[i] = chainStart + i
+	}
+	permute(rootSeq, 0)
+
+	var maxOutput int
+	for _, seq := range permuts {
+		var (
+			commInChans = make([]chan int, chainLen)
+			commOut     = make(chan int, 2)
+		)
+
+		// Create channels
+		for i := range commInChans {
+			commInChans[i] = make(chan int, 2)
+		}
+
+		// Build execution chain
+		for i := 0; i < chainLen-1; i++ {
+			go executeIntcode(cloneIntcode(code), commInChans[i], commInChans[i+1])
+		}
+		go executeIntcode(cloneIntcode(code), commInChans[chainLen-1], commOut)
+
+		// Initialize chain
+		for i, v := range seq {
+			commInChans[i] <- v
+		}
+		commInChans[0] <- 0 // Input signal
+
+		var lastOutput int
+		for r := range commOut {
+			lastOutput = r
+			if looped {
+				commInChans[0] <- r
+			}
+		}
+
+		// Test output of last execution
+		if lastOutput > maxOutput {
+			maxOutput = lastOutput
+		}
+	}
+
+	return maxOutput
+}
+
+func solveDay7Part1(inFile string) (int, error) {
+	raw, err := ioutil.ReadFile(inFile)
+	if err != nil {
+		return 0, errors.Wrap(err, "Unable to read input file")
+	}
+
+	code, err := parseIntcode(strings.TrimSpace(string(raw)))
+	if err != nil {
+		return 0, errors.Wrap(err, "Unable to parse intcode program")
+	}
+
+	return day07TestMaxOutputFromChain(code, 0, 4, false), nil
+}
+
+func solveDay7Part2(inFile string) (int, error) {
+	raw, err := ioutil.ReadFile(inFile)
+	if err != nil {
+		return 0, errors.Wrap(err, "Unable to read input file")
+	}
+
+	code, err := parseIntcode(strings.TrimSpace(string(raw)))
+	if err != nil {
+		return 0, errors.Wrap(err, "Unable to parse intcode program")
+	}
+
+	return day07TestMaxOutputFromChain(code, 5, 9, true), nil
+}

day07_input.txt

@@ -0,0 +1 @@
+3,8,1001,8,10,8,105,1,0,0,21,46,59,84,93,102,183,264,345,426,99999,3,9,1002,9,4,9,1001,9,3,9,102,2,9,9,1001,9,5,9,102,3,9,9,4,9,99,3,9,1002,9,3,9,101,4,9,9,4,9,99,3,9,1002,9,4,9,1001,9,4,9,102,2,9,9,1001,9,2,9,1002,9,3,9,4,9,99,3,9,1001,9,5,9,4,9,99,3,9,1002,9,4,9,4,9,99,3,9,101,2,9,9,4,9,3,9,102,2,9,9,4,9,3,9,1001,9,1,9,4,9,3,9,1001,9,1,9,4,9,3,9,1002,9,2,9,4,9,3,9,101,1,9,9,4,9,3,9,1001,9,2,9,4,9,3,9,102,2,9,9,4,9,3,9,1001,9,2,9,4,9,3,9,1002,9,2,9,4,9,99,3,9,101,1,9,9,4,9,3,9,102,2,9,9,4,9,3,9,1001,9,2,9,4,9,3,9,101,2,9,9,4,9,3,9,101,2,9,9,4,9,3,9,101,2,9,9,4,9,3,9,1002,9,2,9,4,9,3,9,101,2,9,9,4,9,3,9,1001,9,1,9,4,9,3,9,101,1,9,9,4,9,99,3,9,1002,9,2,9,4,9,3,9,1002,9,2,9,4,9,3,9,101,1,9,9,4,9,3,9,1002,9,2,9,4,9,3,9,101,2,9,9,4,9,3,9,1001,9,2,9,4,9,3,9,101,2,9,9,4,9,3,9,101,1,9,9,4,9,3,9,1002,9,2,9,4,9,3,9,102,2,9,9,4,9,99,3,9,102,2,9,9,4,9,3,9,102,2,9,9,4,9,3,9,1001,9,1,9,4,9,3,9,1001,9,1,9,4,9,3,9,101,1,9,9,4,9,3,9,102,2,9,9,4,9,3,9,102,2,9,9,4,9,3,9,1002,9,2,9,4,9,3,9,102,2,9,9,4,9,3,9,1001,9,1,9,4,9,99,3,9,101,1,9,9,4,9,3,9,1002,9,2,9,4,9,3,9,102,2,9,9,4,9,3,9,1002,9,2,9,4,9,3,9,101,1,9,9,4,9,3,9,101,1,9,9,4,9,3,9,1001,9,2,9,4,9,3,9,101,2,9,9,4,9,3,9,101,1,9,9,4,9,3,9,101,1,9,9,4,9,99

day07_test.go

@@ -0,0 +1,91 @@
+package aoc2019
+
+import "testing"
+
+func TestChainedInput(t *testing.T) {
+	code, err := parseIntcode("3,15,3,16,1002,16,10,16,1,16,15,15,4,15,99,0,0")
+	if err != nil {
+		t.Fatalf("Intcode parser failed: %s", err)
+	}
+
+	// Create channels
+	var (
+		aIn  = make(chan int, 2)
+		bIn  = make(chan int, 2)
+		cIn  = make(chan int, 2)
+		dIn  = make(chan int, 2)
+		eIn  = make(chan int, 2)
+		eOut = make(chan int, 2)
+	)
+
+	// Build execution chain
+	go executeIntcode(cloneIntcode(code), aIn, bIn)
+	go executeIntcode(cloneIntcode(code), bIn, cIn)
+	go executeIntcode(cloneIntcode(code), cIn, dIn)
+	go executeIntcode(cloneIntcode(code), dIn, eIn)
+	go executeIntcode(cloneIntcode(code), eIn, eOut)
+
+	// Initialize chain
+	aIn <- 4 // Sequence
+	aIn <- 0 // Input signal
+	bIn <- 3 // Sequence
+	cIn <- 2 // Sequence
+	dIn <- 1 // Sequence
+	eIn <- 0 // Sequence
+
+	// Test output of last execution
+	if r := <-eOut; r != 43210 {
+		t.Errorf("Unexpected result from chain: exp=43210 got=%d", r)
+	}
+}
+
+func TestMaxOutputFromChain(t *testing.T) {
+	for codeStr, expValue := range map[string]int{
+		"3,15,3,16,1002,16,10,16,1,16,15,15,4,15,99,0,0":                                                      43210,
+		"3,23,3,24,1002,24,10,24,1002,23,-1,23,101,5,23,23,1,24,23,23,4,23,99,0,0":                            54321,
+		"3,31,3,32,1002,32,10,32,1001,31,-2,31,1007,31,0,33,1002,33,7,33,1,33,31,31,1,32,31,31,4,31,99,0,0,0": 65210,
+	} {
+		code, err := parseIntcode(codeStr)
+		if err != nil {
+			t.Fatalf("Parsing Intcode failed: %s", err)
+		}
+
+		if r := day07TestMaxOutputFromChain(code, 0, 4, false); r != expValue {
+			t.Errorf("Max output yield unexpected result: exp=%d got=%d", expValue, r)
+		}
+	}
+}
+
+func TestMaxOutputFromLoopedChain(t *testing.T) {
+	for codeStr, expValue := range map[string]int{
+		"3,26,1001,26,-4,26,3,27,1002,27,2,27,1,27,26,27,4,27,1001,28,-1,28,1005,28,6,99,0,0,5":                                                                                         139629729,
+		"3,52,1001,52,-5,52,3,53,1,52,56,54,1007,54,5,55,1005,55,26,1001,54,-5,54,1105,1,12,1,53,54,53,1008,54,0,55,1001,55,1,55,2,53,55,53,4,53,1001,56,-1,56,1005,56,6,99,0,0,0,0,10": 18216,
+	} {
+		code, err := parseIntcode(codeStr)
+		if err != nil {
+			t.Fatalf("Parsing Intcode failed: %s", err)
+		}
+
+		if r := day07TestMaxOutputFromChain(code, 5, 9, true); r != expValue {
+			t.Errorf("Max output yield unexpected result: exp=%d got=%d", expValue, r)
+		}
+	}
+}
+
+func TestCalculateDay7_Part1(t *testing.T) {
+	codeP0, err := solveDay7Part1("day07_input.txt")
+	if err != nil {
+		t.Fatalf("Day 7 solver failed: %s", err)
+	}
+
+	t.Logf("Solution Day 7 Part 1: %d", codeP0)
+}
+
+func TestCalculateDay7_Part2(t *testing.T) {
+	result, err := solveDay7Part2("day07_input.txt")
+	if err != nil {
+		t.Fatalf("Day 7 solver failed: %s", err)
+	}
+
+	t.Logf("Solution Day 7 Part 2: %d", result)
+}

intcode.go

@@ -63,6 +63,14 @@ func parseOpCode(in int) opCode {
 	return out
 }
 
+func cloneIntcode(in []int) []int {
+	out := make([]int, len(in))
+	for i, v := range in {
+		out[i] = v
+	}
+	return out
+}
+
 func parseIntcode(code string) ([]int, error) {
 	parts := strings.Split(code, ",")