Day 7 part 2

2019/src/bin/day5.rs

@@ -5,11 +5,11 @@ fn main() -> io::Result<()> {
     let input = fs::read_to_string("input/day5.txt")?;
     let data = input::read_separated_line(',', &input)?;
 
-    let mut computer = computer::Computer::new(data.clone(), vec![1], vec![]);
+    let mut computer = computer::Computer::new('1', data.clone(), vec![1], vec![]);
     computer.run(None, None);
     println!("Part 1:  {}", computer.output());
 
-    let mut computer = computer::Computer::new(data.clone(), vec![5], vec![]);
+    let mut computer = computer::Computer::new('2', data.clone(), vec![5], vec![]);
     computer.run(None, None);
     println!("Part 2:  {}", computer.output());
 

2019/src/bin/day7.rs

@@ -1,6 +1,10 @@
 use std::{fs, io};
 
-use advent_of_code::{computer, input};
+use advent_of_code::computer::{ComputeResult, Computer, Output, Pipe};
+use advent_of_code::input;
+use std::cell::RefCell;
+use std::convert::TryFrom;
+use std::rc::Rc;
 
 const AMPLIFIERS: usize = 5;
 
@@ -9,7 +13,7 @@ fn main() -> io::Result<()> {
     let data = input::read_separated_line(',', &source)?;
 
     part1(data.clone());
-    //    part2(data);
+    part2(data);
 
     Ok(())
 }
@@ -20,12 +24,14 @@ fn part1(data: Vec<i32>) {
         elements[i as usize] = i;
     }
     let max = phase_settings(elements)
-        .iter()
+        .into_iter()
         .map(|settings| {
             let mut output = 0;
+            let mut name = 'A';
             for phase_setting in settings.iter() {
                 let input = vec![output, *phase_setting];
-                let mut computer = computer::Computer::new(data.clone(), input, vec![]);
+                let mut computer = Computer::new(name, data.clone(), input, vec![]);
+                name = char::try_from(name as u32 + 1).unwrap();
                 computer.run(None, None);
                 output = computer.output();
             }
@@ -42,7 +48,68 @@ fn part2(data: Vec<i32>) {
         elements[i as usize - 5] = i;
     }
 
-    // println!("Part 2: {}", max);
+    let max = phase_settings(elements)
+        .into_iter()
+        .map(|settings| run_part2_with_settings(data.clone(), settings))
+        .max()
+        .unwrap();
+
+    println!("Part 2: {}", max);
+}
+
+fn run_part2_with_settings(data: Vec<i32>, settings: [i32; AMPLIFIERS]) -> i32 {
+    // Construct the amplifiers and the pipes between them
+    // The first amplifier gets io_pipe as input
+    // The last amplifier gets io_pipe as output
+    // otherwise the get a pipe between them
+    let io_pipe = Rc::new(RefCell::new(Pipe::new(vec![0].into_iter().collect())));
+    let mut last_pipe = Rc::clone(&io_pipe);
+    let mut amplifiers = Vec::with_capacity(AMPLIFIERS);
+    for i in 0..AMPLIFIERS {
+        let next_pipe = if i == AMPLIFIERS - 1 {
+            // This is the last amplifier, its output goes to the input of the first
+            Rc::clone(&io_pipe)
+        } else {
+            Rc::new(RefCell::new(Pipe::new(vec![].into_iter().collect())))
+        };
+        // Add the phase setting (it's the first thing that's read)
+        last_pipe.borrow_mut().push_front(settings[i]);
+        let amp = Computer::new(
+            char::try_from('A' as u32 + i as u32).unwrap(),
+            data.clone(),
+            last_pipe,
+            Rc::clone(&next_pipe),
+        );
+        amplifiers.push(amp);
+        last_pipe = next_pipe;
+    }
+
+    // Now run them
+    let mut i = 0;
+    let mut halted = Vec::with_capacity(AMPLIFIERS);
+    loop {
+        match amplifiers[i].run(None, None) {
+            ComputeResult::Halted => {
+                let amp = amplifiers.remove(i);
+                println!("{} halted", amp.name());
+                halted.push(amp);
+                if amplifiers.is_empty() {
+                    break;
+                }
+                // Don't increment i as we removed an element
+                i = i % amplifiers.len();
+            }
+            ComputeResult::NeedsInput => {
+                println!("{} needs input", amplifiers[i].name());
+                // continue to next one
+                i = (i + 1) % amplifiers.len();
+            }
+        }
+    }
+
+    // Need the last output sent from the last amplifier
+    dbg!(io_pipe.borrow());
+    io_pipe.last_value()
 }
 
 fn phase_settings(mut elements: [i32; AMPLIFIERS]) -> Vec<[i32; AMPLIFIERS]> {
@@ -73,7 +140,7 @@ mod tests {
 
     #[test]
     fn test_phase_setting_generation() {
-        let settings = phase_settings();
+        let settings = phase_settings([0, 1, 2, 3, 4]);
         assert_eq!(
             &settings[0..6],
             &[
@@ -86,4 +153,31 @@ mod tests {
             ]
         );
     }
+
+    #[test]
+    fn test_part2_example1() {
+        let input = vec![
+            3, 26, 1001, 26, -4, 26, 3, 27, 1002, 27, 2, 27, 1, 27, 26, 27, 4, 27, 1001, 28, -1,
+            28, 1005, 28, 6, 99, 0, 0, 5,
+        ];
+        assert_eq!(run_part2_with_settings(input, [9, 8, 7, 6, 5]), 139629729);
+    }
+
+    #[test]
+    fn test_part2_example2() {
+        let input = vec![
+            3, 52, 1001, 52, -5, 52, 3, 53, 1, 52, 56, 54, 1007, 54, 5, 55, 1005, 55, 26, 1001, 54,
+            -5, 54, 1105, 1, 12, 1, 53, 54, 53, 1008, 54, 0, 55, 1001, 55, 1, 55, 2, 53, 55, 53, 4,
+            53, 1001, 56, -1, 56, 1005, 56, 6, 99, 0, 0, 0, 0, 10,
+        ];
+        assert_eq!(run_part2_with_settings(input, [9, 7, 8, 5, 6]), 18216);
+    }
+
+    #[test]
+    fn test_part2_with_part1_example() {
+        let input = vec![
+            3, 15, 3, 16, 1002, 16, 10, 16, 1, 16, 15, 15, 4, 15, 99, 0, 0,
+        ];
+        assert_eq!(run_part2_with_settings(input, [4, 3, 2, 1, 0]), 43210);
+    }
 }

2019/src/computer.rs

@@ -1,3 +1,7 @@
+use std::cell::RefCell;
+use std::collections::VecDeque;
+use std::rc::Rc;
+
 type Address = i32;
 
 #[derive(Debug, Eq, PartialEq)]
@@ -19,7 +23,20 @@ enum Mode {
     Address,
 }
 
+#[derive(Debug)]
+pub struct Pipe {
+    queue: VecDeque<i32>,
+    last: Option<i32>,
+}
+
+pub enum ComputeResult {
+    Halted,
+    NeedsInput,
+}
+
 pub struct Computer<I: Input, O: Output> {
+    name: char,
+    ip: i32,
     memory: Vec<i32>,
     input: I,
     output: O,
@@ -51,6 +68,24 @@ impl Output for Vec<i32> {
     }
 }
 
+impl Input for Rc<RefCell<Pipe>> {
+    fn read(&mut self) -> Option<i32> {
+        dbg!(self.borrow_mut().queue.pop_front())
+    }
+}
+
+impl Output for Rc<RefCell<Pipe>> {
+    fn write(&mut self, value: i32) {
+        let mut pipe = self.borrow_mut();
+        pipe.last = Some(value);
+        pipe.queue.push_back(value);
+    }
+
+    fn last_value(&self) -> i32 {
+        self.borrow().last.unwrap()
+    }
+}
+
 fn decode(mut instruction: i32) -> Instruction {
     let opcode = divmod(&mut instruction, 100);
 
@@ -90,15 +125,25 @@ fn decode(mut instruction: i32) -> Instruction {
     }
 }
 
-impl<I, O> Computer<I, O> where I: Input, O: Output {
-    pub fn new(memory: Vec<i32>, input: I, output: O) -> Self {
+impl<I, O> Computer<I, O>
+where
+    I: Input,
+    O: Output,
+{
+    pub fn new(name: char, memory: Vec<i32>, input: I, output: O) -> Self {
         Computer {
+            name,
+            ip: 0,
             memory,
             input,
             output,
         }
     }
 
+    pub fn name(&self) -> char {
+        self.name
+    }
+
     fn read(&self, value: i32, mode: Mode) -> i32 {
         match mode {
             Mode::Immediate => self.memory[value as usize],
@@ -110,67 +155,74 @@ impl<I, O> Computer<I, O> where I: Input, O: Output {
         self.memory[address as usize] = value;
     }
 
-    pub fn run(&mut self, noun: Option<i32>, verb: Option<i32>) {
+    pub fn run(&mut self, noun: Option<i32>, verb: Option<i32>) -> ComputeResult {
+        println!("{}: resume ip = {}", self.name, self.ip);
         if let Some(noun) = noun {
             self.write(1, noun);
         }
         if let Some(verb) = verb {
             self.write(2, verb);
         }
-        let mut ip = 0; // instruction pointer
 
         loop {
-            match decode(self.read(ip, Mode::Immediate)) {
+            match decode(self.read(self.ip, Mode::Immediate)) {
                 Instruction::Add(mode1, mode2) => {
-                    let result = self.read(ip + 1, mode1) + self.read(ip + 2, mode2);
-                    self.write(self.read(ip + 3, Mode::Immediate), result);
-                    ip += 4;
+                    let result = self.read(self.ip + 1, mode1) + self.read(self.ip + 2, mode2);
+                    self.write(self.read(self.ip + 3, Mode::Immediate), result);
+                    self.ip += 4;
                 }
                 Instruction::Multiply(mode1, mode2) => {
-                    let result = self.read(ip + 1, mode1) * self.read(ip + 2, mode2);
-                    self.write(self.read(ip + 3, Mode::Immediate), result);
-                    ip += 4;
-                }
-                Instruction::Input => {
-                    let value = self.input.read().expect("no more input");
-                    self.write(self.read(ip + 1, Mode::Immediate), value);
-                    ip += 2;
+                    let result = self.read(self.ip + 1, mode1) * self.read(self.ip + 2, mode2);
+                    self.write(self.read(self.ip + 3, Mode::Immediate), result);
+                    self.ip += 4;
                 }
+                Instruction::Input => match self.input.read() {
+                    Some(value) => {
+                        self.write(self.read(self.ip + 1, Mode::Immediate), value);
+                        self.ip += 2;
+                    }
+                    None => {
+                        // println!("{}: pause ip = {}", self.name, self.ip);
+                        return ComputeResult::NeedsInput;
+                    }
+                },
                 Instruction::Output(mode) => {
-                    self.output.write(self.read(ip + 1, mode));
-                    ip += 2;
+                    let value = self.read(self.ip + 1, mode);
+                    println!("{}: output {}", self.name, value);
+                    self.output.write(value);
+                    self.ip += 2;
                 }
                 Instruction::JumpIfTrue(mode1, mode2) => {
-                    if self.read(ip + 1, mode1) != 0 {
-                        ip = self.read(ip + 2, mode2);
+                    if self.read(self.ip + 1, mode1) != 0 {
+                        self.ip = self.read(self.ip + 2, mode2);
                     } else {
-                        ip += 3;
+                        self.ip += 3;
                     }
                 }
                 Instruction::JumpIfFalse(mode1, mode2) => {
-                    if self.read(ip + 1, mode1) == 0 {
-                        ip = self.read(ip + 2, mode2);
+                    if self.read(self.ip + 1, mode1) == 0 {
+                        self.ip = self.read(self.ip + 2, mode2);
                     } else {
-                        ip += 3;
+                        self.ip += 3;
                     }
                 }
                 Instruction::LessThan(mode1, mode2) => {
-                    if self.read(ip + 1, mode1) < self.read(ip + 2, mode2) {
-                        self.write(self.read(ip + 3, Mode::Immediate), 1);
+                    if self.read(self.ip + 1, mode1) < self.read(self.ip + 2, mode2) {
+                        self.write(self.read(self.ip + 3, Mode::Immediate), 1);
                     } else {
-                        self.write(self.read(ip + 3, Mode::Immediate), 0);
+                        self.write(self.read(self.ip + 3, Mode::Immediate), 0);
                     }
-                    ip += 4;
+                    self.ip += 4;
                 }
                 Instruction::Equals(mode1, mode2) => {
-                    if self.read(ip + 1, mode1) == self.read(ip + 2, mode2) {
-                        self.write(self.read(ip + 3, Mode::Immediate), 1);
+                    if self.read(self.ip + 1, mode1) == self.read(self.ip + 2, mode2) {
+                        self.write(self.read(self.ip + 3, Mode::Immediate), 1);
                     } else {
-                        self.write(self.read(ip + 3, Mode::Immediate), 0);
+                        self.write(self.read(self.ip + 3, Mode::Immediate), 0);
                     }
-                    ip += 4;
+                    self.ip += 4;
                 }
-                Instruction::Halt => break,
+                Instruction::Halt => return ComputeResult::Halted,
             }
         }
     }
@@ -180,6 +232,16 @@ impl<I, O> Computer<I, O> where I: Input, O: Output {
     }
 }
 
+impl Pipe {
+    pub fn new(queue: VecDeque<i32>) -> Self {
+        Pipe { queue, last: None }
+    }
+
+    pub fn push_front(&mut self, value: i32) {
+        self.queue.push_front(value);
+    }
+}
+
 fn divmod(value: &mut i32, divisor: i32) -> i32 {
     let res = *value % divisor;
     *value /= divisor;
@@ -213,8 +275,8 @@ mod tests {
     #[test]
     fn test_day2() {
         let input = fs::read_to_string("input/day2.txt").unwrap();
-        let mut data = input::read_separated_line(',', &input).unwrap();
-        let mut program = Computer::new(&mut data, vec![]);
+        let data = input::read_separated_line(',', &input).unwrap();
+        let mut program = Computer::new('2', data, vec![], vec![]);
 
         // Check that day2 still works wirh run through this implementation
         program.run(Some(12), Some(2));