2020 Day 8 Complete!

2020/day08/main.go

@@ -0,0 +1,60 @@
+package main
+
+import (
+	"fmt"
+	"strings"
+
+	h "git.bullercodeworks.com/brian/adventofcode/helpers"
+)
+
+func main() {
+	fmt.Println("# Day 7")
+	inp := h.StdinToStringSlice()
+	FixProg(inp)
+}
+
+func RunProg(inp []string) {
+	var acc int
+	var ptr int
+	hist := make(map[int]int)
+	for ptr < len(inp) {
+		if _, ok := hist[ptr]; ok {
+			fmt.Printf("Instruction %d repeated. Acc: %d\n", ptr, acc)
+			return
+		}
+		hist[ptr] = acc
+		pts := strings.Split(inp[ptr], " ")
+		switch pts[0] {
+		case "acc":
+			acc = acc + h.Atoi(pts[1])
+			ptr++
+		case "jmp":
+			ptr = ptr + h.Atoi(pts[1])
+		case "nop":
+			ptr++
+		}
+	}
+}
+
+func FixProg(inp []string) {
+	p := NewProgram(inp)
+	chchch := p.CountOpCodes(NOP, JMP)
+	for ch := 1; ch <= chchch; ch++ {
+		np := p.Copy()
+		chOp := np.FindNthOp(ch, NOP, JMP)
+		if chOp >= 0 {
+			if np.Instructions[chOp].OpCode == NOP {
+				np.Instructions[chOp].OpCode = JMP
+			} else if np.Instructions[chOp].OpCode == JMP {
+				np.Instructions[chOp].OpCode = NOP
+			}
+			res := np.Run()
+			if res == 0 {
+				fmt.Println("Accumulator:", np.Accumulator)
+				return
+			}
+		}
+		fmt.Println("Changing", ch, "didn't fix it")
+	}
+	fmt.Println("Failed to fix program")
+}