Created
December 7, 2019 05:43
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| use itertools::Itertools; | |
| use std::io; | |
| #[derive(Debug, Default)] | |
| struct VM { | |
| pc: usize, | |
| opcode: i32, | |
| mem: Vec<i32>, | |
| input_state: usize, | |
| phase: i32, | |
| signal_in: i32, | |
| signal_out: i32, | |
| } | |
| #[derive(Copy, Clone, Debug, PartialEq, Eq)] | |
| enum ExecutionState { | |
| Suspended, | |
| Done, | |
| } | |
| impl VM { | |
| fn get(&mut self) -> i32 { | |
| let val = self.mem[self.pc]; | |
| let result = match self.opcode % 10 { | |
| 0 => self.mem[val as usize], | |
| 1 => val, | |
| _ => panic!("Unexpected indirection mode"), | |
| }; | |
| self.pc += 1; | |
| self.opcode /= 10; | |
| result | |
| } | |
| fn set(&mut self, val: i32) { | |
| let target = self.mem[self.pc] as usize; | |
| self.mem[target] = val; | |
| self.pc += 1; | |
| } | |
| fn run(&mut self) -> ExecutionState { | |
| use ExecutionState::*; | |
| loop { | |
| self.opcode = self.mem[self.pc]; | |
| let op = self.opcode % 100; | |
| self.opcode /= 100; | |
| self.pc += 1; | |
| match op { | |
| 1 => { | |
| let val = self.get() + self.get(); | |
| self.set(val); | |
| } | |
| 2 => { | |
| let val = self.get() * self.get(); | |
| self.set(val); | |
| } | |
| 3 => { | |
| if self.input_state == 0 { | |
| self.set(self.phase); | |
| } else if self.input_state == 1 { | |
| self.set(self.signal_in); | |
| } else { | |
| self.pc -= 1; | |
| self.input_state -= 1; | |
| return Suspended; | |
| } | |
| self.input_state += 1; | |
| } | |
| 4 => { | |
| self.signal_out = self.get(); | |
| } | |
| 5 => { | |
| let cond = self.get(); | |
| let target = self.get() as usize; | |
| if cond != 0 { | |
| self.pc = target; | |
| } | |
| } | |
| 6 => { | |
| let cond = self.get(); | |
| let target = self.get() as usize; | |
| if cond == 0 { | |
| self.pc = target; | |
| } | |
| } | |
| 7 => { | |
| let val = if self.get() < self.get() { 1 } else { 0 }; | |
| self.set(val); | |
| } | |
| 8 => { | |
| let val = if self.get() == self.get() { 1 } else { 0 }; | |
| self.set(val); | |
| } | |
| 99 => return Done, | |
| x => panic!("Unexpected opcode: {}", x), | |
| }; | |
| } | |
| } | |
| } | |
| fn main() { | |
| let mut buf = String::new(); | |
| io::stdin().read_line(&mut buf).unwrap(); | |
| let mem: Vec<i32> = buf | |
| .trim_end() | |
| .split(',') | |
| .map(|x| x.parse().unwrap()) | |
| .collect(); | |
| println!( | |
| "{}", | |
| (5..10) | |
| .permutations(5) | |
| .map(|c| { | |
| let mut vms: Vec<_> = c | |
| .into_iter() | |
| .map(|phase| VM { | |
| mem: mem.clone(), | |
| phase, | |
| ..Default::default() | |
| }) | |
| .collect(); | |
| let mut signal = 0; | |
| 'outer: loop { | |
| for (i, vm) in vms.iter_mut().enumerate() { | |
| vm.signal_in = signal; | |
| if vm.run() == ExecutionState::Done && i == 4 { | |
| break 'outer vm.signal_out; | |
| } | |
| signal = vm.signal_out; | |
| } | |
| } | |
| }) | |
| .max() | |
| .unwrap() | |
| ); | |
| } |
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