From f3c1072d08c82950f1e55006d8e401aae64ed61b Mon Sep 17 00:00:00 2001
From: hal8174 <henning.lindemann@pm.me>
Date: Wed, 18 Dec 2024 21:54:34 +0100
Subject: [PATCH] Partial solve day 17

---
 Cargo.lock     |   1 +
 Cargo.toml     |   1 +
 input/17-0a.in |   5 ++
 input/17-0b.in |   5 ++
 input/17-1.in  |   5 ++
 src/bin/17.rs  | 166 +++++++++++++++++++++++++++++++++++++++++++++++++
 6 files changed, 183 insertions(+)
 create mode 100644 input/17-0a.in
 create mode 100644 input/17-0b.in
 create mode 100644 input/17-1.in
 create mode 100644 src/bin/17.rs

diff --git a/Cargo.lock b/Cargo.lock
index 44589ff..f0a2d4f 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -15,6 +15,7 @@ dependencies = [
  "image",
  "itertools 0.13.0",
  "memoize",
+ "rayon",
  "regex",
 ]
 
diff --git a/Cargo.toml b/Cargo.toml
index d142b41..97ed37b 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -7,4 +7,5 @@ edition = "2021"
 image = "0.25.5"
 itertools = "0.13.0"
 memoize = "0.4.2"
+rayon = "1.10.0"
 regex = "1.11.1"
diff --git a/input/17-0a.in b/input/17-0a.in
new file mode 100644
index 0000000..f09839b
--- /dev/null
+++ b/input/17-0a.in
@@ -0,0 +1,5 @@
+Register A: 729
+Register B: 0
+Register C: 0
+
+Program: 0,1,5,4,3,0
diff --git a/input/17-0b.in b/input/17-0b.in
new file mode 100644
index 0000000..4a91c26
--- /dev/null
+++ b/input/17-0b.in
@@ -0,0 +1,5 @@
+Register A: 2024
+Register B: 0
+Register C: 0
+
+Program: 0,3,5,4,3,0
diff --git a/input/17-1.in b/input/17-1.in
new file mode 100644
index 0000000..fb81fbe
--- /dev/null
+++ b/input/17-1.in
@@ -0,0 +1,5 @@
+Register A: 27575648
+Register B: 0
+Register C: 0
+
+Program: 2,4,1,2,7,5,4,1,1,3,5,5,0,3,3,0
diff --git a/src/bin/17.rs b/src/bin/17.rs
new file mode 100644
index 0000000..41feadd
--- /dev/null
+++ b/src/bin/17.rs
@@ -0,0 +1,166 @@
+use rayon::prelude::*;
+
+fn combo_operand(operand: u8, a: u64, b: u64, c: u64) -> u64 {
+    match operand {
+        0..4 => operand as u64,
+        4 => a,
+        5 => b,
+        6 => c,
+        _ => unreachable!(),
+    }
+}
+
+fn run_program(program: &[u8], mut a: u64, mut b: u64, mut c: u64) -> Vec<u8> {
+    let mut i = 0;
+
+    let mut output = Vec::new();
+
+    while let Some((&opcode, &operand)) = program.get(i).zip(program.get(i + 1)) {
+        // dbg!(i, a, b, c, opcode, operand);
+        match opcode {
+            0 => {
+                a = a / (2u64.pow(combo_operand(operand, a, b, c) as u32));
+                i += 2
+            }
+            1 => {
+                b ^= operand as u64;
+                i += 2;
+            }
+            2 => {
+                b = combo_operand(operand, a, b, c) % 8;
+                i += 2
+            }
+            3 => {
+                if a != 0 {
+                    i = operand as usize
+                } else {
+                    i += 2;
+                }
+            }
+            4 => {
+                b ^= c;
+                i += 2;
+            }
+            5 => {
+                output.push((combo_operand(operand, a, b, c) % 8) as u8);
+                i += 2;
+            }
+            6 => {
+                b = a / (2u64.pow(combo_operand(operand, a, b, c) as u32));
+                i += 2
+            }
+            7 => {
+                c = a / (2u64.pow(combo_operand(operand, a, b, c) as u32));
+                i += 2
+            }
+
+            _ => unreachable!(),
+        }
+    }
+
+    output
+}
+
+fn run_program_output(program: &[u8], mut a: u64, mut b: u64, mut c: u64) -> bool {
+    let mut i = 0;
+
+    let mut o = 0;
+
+    while let Some((&opcode, &operand)) = program.get(i).zip(program.get(i + 1)) {
+        // dbg!(i, a, b, c, opcode, operand);
+        match opcode {
+            0 => {
+                a = a / (2u64.pow(combo_operand(operand, a, b, c) as u32));
+                i += 2
+            }
+            1 => {
+                b ^= operand as u64;
+                i += 2;
+            }
+            2 => {
+                b = combo_operand(operand, a, b, c) % 8;
+                i += 2
+            }
+            3 => {
+                if a != 0 {
+                    i = operand as usize
+                } else {
+                    i += 2;
+                }
+            }
+            4 => {
+                b ^= c;
+                i += 2;
+            }
+            5 => {
+                if program.len() >= o && program[o] != (combo_operand(operand, a, b, c) % 8) as u8 {
+                    return false;
+                }
+                o += 1;
+                i += 2;
+            }
+            6 => {
+                b = a / (2u64.pow(combo_operand(operand, a, b, c) as u32));
+                i += 2
+            }
+            7 => {
+                c = a / (2u64.pow(combo_operand(operand, a, b, c) as u32));
+                i += 2
+            }
+
+            _ => unreachable!(),
+        }
+    }
+
+    o == program.len()
+}
+
+fn main() {
+    let text = std::fs::read_to_string("input/17-1.in").unwrap();
+    let mut lines = text.lines();
+    let start_a = lines
+        .next()
+        .unwrap()
+        .split_once(": ")
+        .unwrap()
+        .1
+        .parse::<u64>()
+        .unwrap();
+    let start_b = lines
+        .next()
+        .unwrap()
+        .split_once(": ")
+        .unwrap()
+        .1
+        .parse::<u64>()
+        .unwrap();
+    let start_c = lines
+        .next()
+        .unwrap()
+        .split_once(": ")
+        .unwrap()
+        .1
+        .parse::<u64>()
+        .unwrap();
+
+    let program = lines
+        .nth(1)
+        .unwrap()
+        .split_once(": ")
+        .unwrap()
+        .1
+        .split(',')
+        .map(|c| c.parse::<u8>().unwrap())
+        .collect::<Vec<_>>();
+
+    println!("{:?}", run_program(&program, start_a, start_b, start_c));
+
+    let start = 1_000_000_000_000u64;
+
+    let t = (start..start * 10)
+        .into_par_iter()
+        .find_first(|&i| run_program_output(&program, i, 0, 0))
+        .unwrap();
+
+    println!("{t}");
+}