might be making a mistake starting 2018...

2019/day02/part2/main.go

@@ -0,0 +1,63 @@
+package main
+
+import (
+	"adventofcode/util"
+	"fmt"
+	"strconv"
+	"strings"
+)
+
+func main() {
+	// read the input file, modify it to a slice of numbers
+	inputFile := util.ReadFile("../input.txt")
+	splitStrings := strings.Split(inputFile, ", ")
+	inputNumbers := make([]int, len(splitStrings))
+
+	for i, v := range splitStrings {
+		inputNumbers[i], _ = strconv.Atoi(v)
+	}
+
+	// brute force to try all options for nouns and verbs
+	for i := 0; i < 100; i++ {
+		for j := 0; j < 100; j++ {
+			// crete a copy of the inputNumbers slice
+			clone := make([]int, 120)
+			copy(clone, inputNumbers)
+			clone[1] = i
+			clone[2] = j
+
+			// run step on the cloned slice
+			step(clone, 0)
+			// check if the zero address is equal to the AoC value
+			if clone[0] == 19690720 {
+				// print answers to console (manually add to advent of code)
+				fmt.Println("noun is", i, "verb is", j)
+				fmt.Println("actual result value noun * 10 + verb = ", i*100+j)
+
+				// return to end main function
+				return
+			}
+		}
+	}
+}
+
+// step will read the next 4 values in the input `sli` and make updates
+// according to the opcodes
+func step(sli []int, index int) bool {
+	if sli[index] == 99 {
+		return false
+	}
+	opcode, two, three, four := read(sli, index)
+	switch opcode {
+	case 1:
+		sli[four] = sli[two] + sli[three]
+	case 2:
+		sli[four] = sli[two] * sli[three]
+	}
+	// recursively call itself & increment index value...
+	return step(sli, index+4)
+}
+
+func read(sli []int, index int) (int, int, int, int) {
+	return sli[index], sli[index+1], sli[index+2], sli[index+3]
+}