add day 1 and 2 solutions

day02/internal/interpreter/interpreter.go

@@ -0,0 +1,61 @@
+package interpreter
+
+import "fmt"
+
+type Interpreter struct {
+	program            []int
+	instructionPointer int
+}
+
+func Init(program []int) *Interpreter {
+    return &Interpreter {
+        program: program,
+        instructionPointer: 0,
+    }
+}
+
+func (i *Interpreter) Next() bool {
+	opcode := i.getValueAtIndex(i.instructionPointer)
+	ipIncrement := 1
+
+	switch opcode {
+	case 1:
+        i.add()
+        ipIncrement = 4
+	case 2:
+        i.mul()
+        ipIncrement = 4
+	case 99:
+		return true
+	default:
+		panic(fmt.Sprintf("unhandled opcode %v at IP %v", opcode, i.instructionPointer))
+	}
+
+	i.instructionPointer += ipIncrement
+
+	return false
+}
+
+func (i *Interpreter) getValueAtIndex(index int) int {
+    return i.program[index]
+}
+
+func (i *Interpreter) setValueAtIndex(index, value int) {
+    i.program[index] = value
+}
+
+func (i *Interpreter) add() {
+    resIndex := i.getValueAtIndex(i.instructionPointer + 3)
+    arg1Index := i.getValueAtIndex(i.instructionPointer + 1)
+    arg2Index := i.getValueAtIndex(i.instructionPointer + 2)
+
+    i.setValueAtIndex(resIndex, i.getValueAtIndex(arg1Index) + i.getValueAtIndex(arg2Index))
+}
+
+func (i *Interpreter) mul() {
+    resIndex := i.getValueAtIndex(i.instructionPointer + 3)
+    arg1Index := i.getValueAtIndex(i.instructionPointer + 1)
+    arg2Index := i.getValueAtIndex(i.instructionPointer + 2)
+
+    i.setValueAtIndex(resIndex, i.getValueAtIndex(arg1Index) * i.getValueAtIndex(arg2Index))
+}

day02/internal/interpreter/interpreter_test.go

@@ -0,0 +1 @@
+package interpreter