2019 Day 02 Complete

2019/day02/main.go

@@ -0,0 +1,92 @@
+package main
+
+import (
+	"bufio"
+	"fmt"
+	"log"
+	"os"
+	"strconv"
+	"strings"
+)
+
+func main() {
+	inp := StdinToString()
+	f := func(c rune) bool {
+		return c == ','
+	}
+	var prog []int
+	for _, v := range strings.FieldsFunc(inp, f) {
+		prog = append(prog, Atoi(v))
+	}
+	//part1(prog)
+	part2(prog)
+}
+
+func part1(prog []int) {
+	for i := 0; i < len(prog); i += 4 {
+		switch prog[i] {
+		case 1:
+			prog[prog[i+3]] = add(prog[i+1], prog[i+2], prog)
+		case 2:
+			prog[prog[i+3]] = mult(prog[i+1], prog[i+2], prog)
+		case 99:
+			printState(prog)
+			os.Exit(0)
+		}
+	}
+}
+
+func part2(prog []int) {
+	for n := 0; n <= 99; n++ {
+		for v := 0; v <= 99; v++ {
+			progcpy := make([]int, len(prog))
+			copy(progcpy, prog)
+			progcpy[1], progcpy[2] = n, v
+			for i := 0; i < len(progcpy); i += 4 {
+				switch prog[i] {
+				case 1:
+					progcpy[progcpy[i+3]] = add(progcpy[i+1], progcpy[i+2], progcpy)
+				case 2:
+					progcpy[progcpy[i+3]] = mult(progcpy[i+1], progcpy[i+2], progcpy)
+				case 99:
+					if progcpy[0] == 19690720 {
+						fmt.Println("Found value:", n, v)
+						fmt.Println("Answer:", (100*n + v))
+						os.Exit(0)
+					}
+					i = len(progcpy)
+				}
+			}
+		}
+	}
+}
+
+func printState(prog []int) {
+	fmt.Println(prog)
+}
+
+func add(i, j int, prog []int) int {
+	return prog[i] + prog[j]
+}
+
+func mult(i, j int, prog []int) int {
+	return prog[i] * prog[j]
+}
+
+func StdinToString() string {
+	var input string
+	scanner := bufio.NewScanner(os.Stdin)
+	for scanner.Scan() {
+		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")
+	}
+	return ret
+}