new strategy, but still not working

day17/reversed.go

@@ -0,0 +1,107 @@
+package main
+
+import (
+	"fmt"
+	"strconv"
+)
+
+func reverseSlice(slice []uint) {
+	for i, j := 0, len(slice)-1; i < j; i, j = i+1, j-1 {
+		slice[i], slice[j] = slice[j], slice[i]
+	}
+}
+
+func compressedProgram(ra uint) []uint {
+	out := make([]uint, 0)
+
+	var A, B uint
+	A = ra
+
+	for {
+		B = ((A % 8) ^ 2) ^ 7 ^ (A >> ((A % 8) ^ 2))
+		A = A >> 3
+
+		out = append(out, B%8)
+
+		if A == 0 {
+			break
+		}
+	}
+
+	return out
+}
+
+func reversedProgram(out []uint) uint {
+	reverseSlice(out)
+	A := uint(0)
+
+	for _, o := range out {
+    
+		// find next n bits so that o is returned
+        n := 2
+        searching := true
+        for searching {
+            n++
+
+            // for every combination of n bits
+		    for i := range 1 << n {
+                A_ := (A << n) + uint(i)
+
+                //fmt.Println("add", i, "as binary with", n, "bits")
+		    	//fmt.Println("old", strconv.FormatUint(uint64(A), 2))
+		    	//fmt.Println("new", strconv.FormatUint(uint64(A_), 2))
+
+		    	if o == ((A_%8)^2)^7^(A_>>((A_%8)^2))%8 {
+		    		A = A_
+		    	    //fmt.Println("valid")
+		    		//fmt.Println("yields", compressedProgram(A))
+                    searching = false
+		    		break
+		    	}
+
+		    	//fmt.Println("invalid")
+		    }
+        }
+
+	}
+	return A
+}
+
+func main() {
+	/*
+
+
+		fmt.Println(input)
+
+		a := uint64(0)
+		for _, elem := range input {
+
+			expected_d := elem ^ 7
+			for b := range 8 {
+				e := uint64(b ^ 2)
+				c := (((a << 3) | uint64(b)) >> (e)) % 8
+				actual_d := c ^ e
+				if uint64(expected_d) == actual_d {
+					fmt.Println(b)
+					fmt.Println(e)
+					fmt.Println(c)
+					a = a << 3
+					a = a | uint64(b)
+					fmt.Println(strconv.FormatUint(a, 2))
+					fmt.Println(a, 2)
+					break
+				}
+			}
+
+		}
+		fmt.Println(a)
+		//fmt.Println(strconv.FormatUint(a, 2))
+	*/
+
+	//fmt.Println(compressedProgram(41644071))
+
+	input := []uint{2, 4, 1, 2, 7, 5, 1, 7, 4, 4, 0, 3, 5, 5, 3, 0}
+	fmt.Println("-- input: ", input, "--")
+	ra := reversedProgram(input)
+	fmt.Println("-- ra:    ", ra, "--")
+}