last 3 days

25/25.go

@@ -0,0 +1,62 @@
+package main
+
+import (
+	"fmt"
+)
+
+// go run 25.go
+
+type instruction struct {
+	state     string
+	condition int
+	write     int
+	move      int
+	newState  string
+}
+
+var production = []instruction{
+	{"a", 0, 1, 1, "b"},
+	{"a", 1, 0, -1, "d"},
+	{"b", 0, 1, 1, "c"},
+	{"b", 1, 0, 1, "f"},
+	{"c", 0, 1, -1, "c"},
+	{"c", 1, 1, -1, "a"},
+	{"d", 0, 0, -1, "e"},
+	{"d", 1, 1, 1, "a"},
+	{"e", 0, 1, -1, "a"},
+	{"e", 1, 0, 1, "b"},
+	{"f", 0, 0, 1, "c"},
+	{"f", 1, 0, 1, "e"},
+}
+
+func main() {
+	fmt.Println(ProcessInstructions(production, 12317297))
+}
+
+func ProcessInstructions(instructions []instruction, count int) int {
+	pos := 0
+	state := instructions[0].state
+	tape := make(map[int]int)
+
+	for i := 0; i < count; i++ {
+
+		for r := range instructions {
+			inst := instructions[r]
+			if inst.state == state && inst.condition == tape[pos] {
+				state = inst.newState
+				tape[pos] = inst.write
+				pos += inst.move
+				break
+			}
+		}
+	}
+
+	cksum := 0
+	for _, v := range tape {
+		if v == 1 {
+			cksum++
+		}
+	}
+
+	return cksum
+}

25/25_test.go

@@ -0,0 +1,22 @@
+package main
+
+import (
+	"testing"
+)
+
+var test = []instruction{
+	{"a", 0, 1, 1, "b"},
+	{"a", 1, 0, -1, "b"},
+	{"b", 0, 1, -1, "a"},
+	{"b", 1, 1, 1, "a"}}
+
+func TestInstructions(t *testing.T) {
+	v := ProcessInstructions(test, 6)
+	if v != 3 {
+		t.Error(
+			"For", test,
+			"expected 3",
+			"got", v,
+		)
+	}
+}