Day 12 Complete

day12/input

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+cpy 1 a
+cpy 1 b
+cpy 26 d
+jnz c 2
+jnz 1 5
+cpy 7 c
+inc d
+dec c
+jnz c -2
+cpy a c
+inc a
+dec b
+jnz b -2
+cpy c b
+dec d
+jnz d -6
+cpy 19 c
+cpy 14 d
+inc a
+dec d
+jnz d -2
+dec c
+jnz c -5

day12/main.go

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+package main
+
+import (
+	"bufio"
+	"fmt"
+	"log"
+	"os"
+	"strconv"
+	"strings"
+)
+
+var regs = map[string]int{
+	"a": 0,
+	"b": 0,
+	"c": 1,
+	"d": 0,
+}
+
+func main() {
+	input := stdinToStringSlice()
+	curr := 0
+	for curr < len(input) {
+		ins := strings.Fields(input[curr])
+		curr++
+		switch ins[0] {
+		case "cpy":
+			src := ins[1]
+			dst := ins[2]
+			// check if the src is a register
+			if v, ok := regs[src]; ok {
+				regs[dst] = v
+			} else {
+				// It's not, must be an int
+				regs[dst] = atoi(src)
+			}
+		case "inc":
+			regs[ins[1]] = regs[ins[1]] + 1
+		case "dec":
+			regs[ins[1]] = regs[ins[1]] - 1
+		case "jnz":
+			v, ok := regs[ins[1]]
+			if !ok {
+				v = atoi(ins[1])
+			}
+			if v != 0 {
+				// Subtract 1 from the jump because we incremented already
+				curr += atoi(ins[2]) - 1
+			}
+		}
+	}
+	PrintState()
+}
+
+// Fancy State Printing
+func PrintState() {
+	datLine := fmt.Sprint("\u2502  a:", regs["a"], "  b:", regs["b"], "  c:", regs["c"], "  d:", regs["d"], "  \u2502")
+	fmt.Println("\u250C" + strings.Repeat("\u2500", len(datLine)-6) + "\u2510")
+	fmt.Println(datLine)
+	fmt.Println("\u2514" + strings.Repeat("\u2500", len(datLine)-6) + "\u2518")
+}
+
+func stdinToStringSlice() []string {
+	var input []string
+	scanner := bufio.NewScanner(os.Stdin)
+	for scanner.Scan() {
+		input = append(input, scanner.Text())
+	}
+	return input
+}
+
+func atoi(i string) int {
+	var ret int
+	var err error
+	if ret, err = strconv.Atoi(i); err != nil {
+		log.Fatal("Invalid Atoi:" + i)
+	}
+	return ret
+}

day12/problem

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+Advent of Code
+
+--- Day 12: Leonardo's Monorail ---
+
+   You finally reach the top floor of this building: a garden with a slanted glass ceiling. Looks like there are no more
+   stars to be had.
+
+   While sitting on a nearby bench amidst some tiger lilies, you manage to decrypt some of the files you extracted from
+   the servers downstairs.
+
+   According to these documents, Easter Bunny HQ isn't just this building - it's a collection of buildings in the nearby
+   area. They're all connected by a local monorail, and there's another building not far from here! Unfortunately, being
+   night, the monorail is currently not operating.
+
+   You remotely connect to the monorail control systems and discover that the boot sequence expects a password. The
+   password-checking logic (your puzzle input) is easy to extract, but the code it uses is strange: it's assembunny code
+   designed for the new computer you just assembled. You'll have to execute the code and get the password.
+
+   The assembunny code you've extracted operates on four registers (a, b, c, and d) that start at 0 and can hold any
+   integer. However, it seems to make use of only a few instructions:
+
+     • cpy x y copies x (either an integer or the value of a register) into register y.
+     • inc x increases the value of register x by one.
+     • dec x decreases the value of register x by one.
+     • jnz x y jumps to an instruction y away (positive means forward; negative means backward), but only if x is not
+       zero.
+
+   The jnz instruction moves relative to itself: an offset of -1 would continue at the previous instruction, while an
+   offset of 2 would skip over the next instruction.
+
+   For example:
+
+ cpy 41 a
+ inc a
+ inc a
+ dec a
+ jnz a 2
+ dec a
+
+   The above code would set register a to 41, increase its value by 2, decrease its value by 1, and then skip the last
+   dec a (because a is not zero, so the jnz a 2 skips it), leaving register a at 42. When you move past the last
+   instruction, the program halts.
+
+   After executing the assembunny code in your puzzle input, what value is left in register a?
+
+   Your puzzle answer was __________.
+
+--- Part Two ---
+
+   As you head down the fire escape to the monorail, you notice it didn't start; register c needs to be initialized to
+   the position of the ignition key.
+
+   If you instead initialize register c to be 1, what value is now left in register a?
+
+   Your puzzle answer was ___________.
+
+References
+
+   Visible links
+   . http://adventofcode.com/
+   . http://adventofcode.com/2016/about
+   . http://adventofcode.com/2016/support
+   . http://adventofcode.com/2016/events
+   . http://adventofcode.com/2016/settings
+   . http://adventofcode.com/2016/auth/logout
+   . http://adventofcode.com/2016
+   . http://adventofcode.com/2016
+   . http://adventofcode.com/2016/leaderboard
+   . http://adventofcode.com/2016/stats
+   . http://adventofcode.com/2016/sponsors
+   . http://adventofcode.com/2016/sponsors
+   . https://www.google.com/search?q=tiger+lilies&tbm=isch
+   . http://adventofcode.com/2016/day/11
+   . https://en.wikipedia.org/wiki/Processor_register
+   . https://en.wikipedia.org/wiki/Integer
+   . https://en.wikipedia.org/wiki/Instruction_set
+   . http://adventofcode.com/2016
+   . http://adventofcode.com/2016/day/12/input