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package main
import (
"fmt"
)
func main() {
fmt.Println("4,6,3,5,6,3,5,2,1,0,")
execute(729, 0, 0, []byte{0, 1, 5, 4, 3, 0})
fmt.Println("7,1,3,4,1,2,6,7,1,")
execute(46187030, 0, 0, []byte{2, 4, 1, 5, 7, 5, 0, 3, 4, 0, 1, 6, 5, 5, 3, 0})
// Example
// while (a != 0) {
// a = a >> 3
// print(a%8)
// }
// Data
// while (a != 0) {
// b = a % 8
// b = b ^ 5
// c = a >> b
// a = a >> 3
// b = b ^ c
// b = b ^ 6
// print(b % 8)
// }
part2([]byte{2, 4, 1, 5, 7, 5, 0, 3, 4, 0, 1, 6, 5, 5, 3, 0})
}
func solve(ops []byte, forOp int, startingA int64) bool {
if forOp < 0 {
fmt.Println(startingA)
return true
}
// For the last iteration, only the last 3 can be non 0.
// So we only have 8 values to test.
// For the other operands to invert, the higher bits are fixed
// so we only check the last 3 bits.
for n := range 8 {
a := (startingA << 3) | int64(n)
b := a % 8
b = b ^ 5
c := a >> b
b = b ^ c
b = b ^ 6
if byte(b%8) == ops[forOp] && solve(ops, forOp-1, a) {
return true
}
}
return false
}
func part2(ops []byte) (a int64) {
solve(ops, len(ops)-1, 0)
return
}
func execute(a, b, c int64, ops []byte) {
pc := 0
readOp := func() (op byte) {
op = ops[pc]
pc++
return
}
getCombo := func(op byte) int64 {
if op <= 3 {
return int64(op)
}
switch op {
case 4:
return a
case 5:
return b
case 6:
return c
}
panic("")
}
for pc < len(ops)-1 {
switch readOp() {
case 0:
a = a >> getCombo(readOp())
case 1:
b = b ^ int64(readOp())
case 2:
b = getCombo(readOp()) % 8
case 3:
if a != 0 {
pc = int(readOp())
}
case 4:
b = b ^ c
pc++
case 5:
fmt.Print(getCombo(readOp()) % 8)
fmt.Print(",")
case 6:
b = a >> getCombo(readOp())
case 7:
c = a >> getCombo(readOp())
}
}
fmt.Println("")
}
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