2017 Complete!

2017/day25/day25.go

@@ -0,0 +1,147 @@
+package main
+
+import (
+	"bufio"
+	"errors"
+	"fmt"
+	"log"
+	"os"
+	"strconv"
+	"strings"
+)
+
+var currState string
+var diagAfterSteps, currStep, currPos int
+
+var allStates map[string]State
+
+var tape map[int]bool
+
+func main() {
+	inp := StdinToStrings()
+	tape = make(map[int]bool)
+	allStates = make(map[string]State)
+
+	// Parse 'Begin' line
+	pts := strings.Split(inp[0], " ")
+	st := pts[len(pts)-1]
+	currState = st[:len(st)-1]
+	pts = strings.Split(inp[1], " ")
+	// Parse 'Diagnostic' line
+	diagAfterSteps = Atoi(pts[5])
+	// Parse all of the 'state' lines
+	for i := 3; i < len(inp); i += 10 {
+		if state, err := NewState(inp[i:]); err == nil {
+			allStates[state.Name] = state
+		}
+	}
+
+	fmt.Println("Beginning in State", currState)
+	fmt.Println("Diagnostic After", diagAfterSteps)
+
+	for i := 0; i < diagAfterSteps; i++ {
+		//fmt.Printf("Steps: %d; State %s; Diag: %d; Tape: %s\n", i, currState, RunDiagnostic(), GetTapeString())
+		currState = allStates[currState].Process()
+	}
+	fmt.Println("Diagnostic Checksum:", RunDiagnostic())
+}
+
+func GetTapeString() string {
+	ret := "[ "
+	min, max := 0, 0
+	for k := range tape {
+		if k < min {
+			min = k
+		}
+		if k > max {
+			max = k
+		}
+	}
+
+	for i := min; i < max; i++ {
+		ret += fmt.Sprint("(", i, tape[i], ") ")
+	}
+	return ret + "]"
+}
+
+func RunDiagnostic() int {
+	var chk int
+	for _, v := range tape {
+		if v {
+			chk++
+		}
+	}
+	return chk
+}
+
+type State struct {
+	Name      string
+	State1Ins Instruction
+	State0Ins Instruction
+}
+
+// NewState takes a slice of strings and returns a state built from the _next_ description found
+func NewState(inp []string) (State, error) {
+	if len(inp) < 9 {
+		return State{}, errors.New("Invalid state instructions")
+	}
+	ret := State{}
+	// The first line should have the state name
+	ln := inp[0]
+	ret.Name = ln[len(ln)-2 : len(ln)-1]
+	ret.State0Ins = NewInstruction(inp[2:5])
+	ret.State1Ins = NewInstruction(inp[6:9])
+
+	return ret, nil
+}
+
+// Process makes the needed changes to the tape and returns the
+// next state
+func (s State) Process() string {
+	ins := s.State0Ins
+	if tape[currPos] {
+		ins = s.State1Ins
+	}
+	tape[currPos] = ins.WriteValue
+	currPos += ins.Move
+	return ins.NextState
+}
+
+type Instruction struct {
+	WriteValue bool
+	Move       int
+	NextState  string
+}
+
+func NewInstruction(inp []string) Instruction {
+	ret := Instruction{}
+	tmp := strings.Split(strings.TrimSpace(inp[0]), " ")
+	ret.WriteValue = (tmp[4][len(tmp[4])-2] == '1')
+	tmp = strings.Split(strings.TrimSpace(inp[1]), " ")
+	ret.Move = 1
+	if tmp[6] == "left." {
+		ret.Move = -1
+	}
+	tmp = strings.Split(strings.TrimSpace(inp[2]), " ")
+	state := tmp[len(tmp)-1]
+	ret.NextState = state[len(state)-2 : len(state)-1]
+	return ret
+}
+
+func Atoi(i string) int {
+	var ret int
+	var err error
+	if ret, err = strconv.Atoi(i); err != nil {
+		log.Fatal("Invalid Atoi")
+	}
+	return ret
+}
+
+func StdinToStrings() []string {
+	var input []string
+	scanner := bufio.NewScanner(os.Stdin)
+	for scanner.Scan() {
+		input = append(input, scanner.Text())
+	}
+	return input
+}

2017/day25/input

@@ -0,0 +1,62 @@
+Begin in state A.
+Perform a diagnostic checksum after 12134527 steps.
+
+In state A:
+  If the current value is 0:
+    - Write the value 1.
+    - Move one slot to the right.
+    - Continue with state B.
+  If the current value is 1:
+    - Write the value 0.
+    - Move one slot to the left.
+    - Continue with state C.
+
+In state B:
+  If the current value is 0:
+    - Write the value 1.
+    - Move one slot to the left.
+    - Continue with state A.
+  If the current value is 1:
+    - Write the value 1.
+    - Move one slot to the right.
+    - Continue with state C.
+
+In state C:
+  If the current value is 0:
+    - Write the value 1.
+    - Move one slot to the right.
+    - Continue with state A.
+  If the current value is 1:
+    - Write the value 0.
+    - Move one slot to the left.
+    - Continue with state D.
+
+In state D:
+  If the current value is 0:
+    - Write the value 1.
+    - Move one slot to the left.
+    - Continue with state E.
+  If the current value is 1:
+    - Write the value 1.
+    - Move one slot to the left.
+    - Continue with state C.
+
+In state E:
+  If the current value is 0:
+    - Write the value 1.
+    - Move one slot to the right.
+    - Continue with state F.
+  If the current value is 1:
+    - Write the value 1.
+    - Move one slot to the right.
+    - Continue with state A.
+
+In state F:
+  If the current value is 0:
+    - Write the value 1.
+    - Move one slot to the right.
+    - Continue with state A.
+  If the current value is 1:
+    - Write the value 1.
+    - Move one slot to the right.
+    - Continue with state E.

2017/day25/testinput

@@ -0,0 +1,22 @@
+Begin in state A.
+Perform a diagnostic checksum after 6 steps.
+
+In state A:
+  If the current value is 0:
+    - Write the value 1.
+    - Move one slot to the right.
+    - Continue with state B.
+  If the current value is 1:
+    - Write the value 0.
+    - Move one slot to the left.
+    - Continue with state B.
+
+In state B:
+  If the current value is 0:
+    - Write the value 1.
+    - Move one slot to the left.
+    - Continue with state A.
+  If the current value is 1:
+    - Write the value 1.
+    - Move one slot to the right.
+    - Continue with state A.