From 82cec9a93f6c51dec4676639b28107517e4a7518 Mon Sep 17 00:00:00 2001
From: Viacheslav Slinko <me@vslinko.ru>
Date: Tue, 24 Dec 2024 23:43:09 +0300
Subject: [PATCH] day24

---
 benches/bench.rs |   3 +-
 src/day24.rs     | 183 +++++++++++++++++++++++++++++++++++++++++++++++
 src/lib.rs       |   3 +-
 3 files changed, 187 insertions(+), 2 deletions(-)
 create mode 100644 src/day24.rs

diff --git a/benches/bench.rs b/benches/bench.rs
index 1019ad3..1761ec9 100644
--- a/benches/bench.rs
+++ b/benches/bench.rs
@@ -50,5 +50,6 @@ benches!(
     // 20, "20.txt",
     // 21, "21.txt",
     // 22, "22.txt",
-    23, "23.txt"
+    // 23, "23.txt",
+    24, "24.txt"
 );
diff --git a/src/day24.rs b/src/day24.rs
new file mode 100644
index 0000000..11b42f8
--- /dev/null
+++ b/src/day24.rs
@@ -0,0 +1,183 @@
+use rustc_hash::{FxBuildHasher, FxHashMap};
+
+const X_Y_SIZE: usize = 45;
+const X_Y_SIZE_U32: u32 = X_Y_SIZE as u32;
+const Z_SIZE: usize = 46;
+const Z_SIZE_U32: u32 = Z_SIZE as u32;
+const GATES_COUNT: usize = 222;
+const INITIAL_VALUE_LINE_LENGTH: usize = 7;
+const INPUT_X_POS: usize = 5;
+const INPUT_Y_POS: usize = X_Y_SIZE * INITIAL_VALUE_LINE_LENGTH + INPUT_X_POS;
+const INPUT_GATES_POS: usize = (X_Y_SIZE + X_Y_SIZE) * INITIAL_VALUE_LINE_LENGTH + 1;
+const X_U32: u32 = b'x' as u32;
+const Y_U32: u32 = b'y' as u32;
+const Z_U32: u32 = b'z' as u32;
+const CONTEXT_SIZE: usize = GATES_COUNT + X_Y_SIZE * 2;
+
+type Key = u32;
+
+struct InitialValue {
+    val: usize,
+}
+
+impl InitialValue {
+    fn new(val: usize) -> Self {
+        InitialValue { val }
+    }
+}
+
+enum GateOperaion {
+    And,
+    Or,
+    Xor,
+}
+
+struct Gate {
+    a: Key,
+    op: GateOperaion,
+    b: Key,
+}
+
+impl Gate {
+    fn new(a: Key, op: GateOperaion, b: Key) -> Self {
+        Gate { a, op, b }
+    }
+}
+
+enum ReadableValue {
+    Initial(InitialValue),
+    Gate(Gate),
+}
+
+type Context = FxHashMap<Key, ReadableValue>;
+
+impl ReadableValue {
+    unsafe fn read(&self, context: &Context) -> usize {
+        match self {
+            ReadableValue::Initial(val) => val.val,
+            ReadableValue::Gate(gate) => {
+                let a = context.get(&gate.a).unwrap_unchecked().read(context);
+                let b = context.get(&gate.b).unwrap_unchecked().read(context);
+
+                match gate.op {
+                    GateOperaion::And => a & b,
+                    GateOperaion::Or => a | b,
+                    GateOperaion::Xor => a ^ b,
+                }
+            }
+        }
+    }
+}
+
+fn key2(prefix: u32, index: u32) -> u32 {
+    if index < 10 {
+        prefix as u32 + 12288 + (index + 48) * 65536
+    } else {
+        prefix as u32 + ((index / 10) + 48) * 256 + ((index % 10) + 48) * 65536
+    }
+}
+
+fn key3(a: u8, b: u8, c: u8) -> u32 {
+    a as u32 + b as u32 * 256 + c as u32 * 65536
+}
+
+pub fn part1(input: &str) -> usize {
+    unsafe { inner1(input) }
+}
+
+unsafe fn inner1(input: &str) -> usize {
+    let input = input.as_bytes();
+    let mut context: Context =
+        FxHashMap::with_capacity_and_hasher(CONTEXT_SIZE, FxBuildHasher::default());
+
+    (0..X_Y_SIZE_U32).for_each(|i| {
+        let index = (i as usize) * INITIAL_VALUE_LINE_LENGTH + INPUT_X_POS;
+        let val = (*input.get_unchecked(index) - b'0') as usize;
+        context.insert(
+            key2(X_U32, i),
+            ReadableValue::Initial(InitialValue::new(val)),
+        );
+    });
+
+    (0..X_Y_SIZE_U32).for_each(|i| {
+        let index = (i as usize) * INITIAL_VALUE_LINE_LENGTH + INPUT_Y_POS;
+        let val = (*input.get_unchecked(index) - b'0') as usize;
+        context.insert(
+            key2(Y_U32, i),
+            ReadableValue::Initial(InitialValue::new(val)),
+        );
+    });
+
+    let mut i = INPUT_GATES_POS;
+    (0..GATES_COUNT).for_each(|_| {
+        let a = key3(
+            *input.get_unchecked(i),
+            *input.get_unchecked(i + 1),
+            *input.get_unchecked(i + 2),
+        );
+
+        let op = match input.get_unchecked(i + 4) {
+            b'X' => {
+                i += 8;
+                GateOperaion::Xor
+            }
+            b'A' => {
+                i += 8;
+                GateOperaion::And
+            }
+            b'O' => {
+                i += 7;
+                GateOperaion::Or
+            }
+            _ => unreachable!(),
+        };
+
+        let b = key3(
+            *input.get_unchecked(i),
+            *input.get_unchecked(i + 1),
+            *input.get_unchecked(i + 2),
+        );
+
+        let to = key3(
+            *input.get_unchecked(i + 7),
+            *input.get_unchecked(i + 8),
+            *input.get_unchecked(i + 9),
+        );
+
+        i += 11;
+
+        context.insert(to, ReadableValue::Gate(Gate::new(a, op, b)));
+    });
+
+    (0..Z_SIZE_U32).rev().fold(0, |acc, i| {
+        acc * 2
+            + context
+                .get(&key2(Z_U32, i))
+                .unwrap_unchecked()
+                .read(&context)
+    })
+}
+
+pub fn part2(_input: &str) -> String {
+    "123".to_string()
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use std::fs::read_to_string;
+
+    #[test]
+    fn test_day24_part1() {
+        let prod_input = read_to_string("./inputs/24.txt").unwrap();
+        let prod_output = read_to_string("./outputs/24p1.txt").unwrap();
+        assert_eq!(part1(&prod_input).to_string(), prod_output);
+    }
+
+    #[test]
+    fn test_day24_part2() {
+        let prod_input = read_to_string("./inputs/24.txt").unwrap();
+        let prod_output = read_to_string("./outputs/24p2.txt").unwrap();
+        assert_eq!(part2(&prod_input).to_string(), prod_output);
+    }
+}
diff --git a/src/lib.rs b/src/lib.rs
index d421501..4b27082 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -23,4 +23,5 @@
 // pub mod day20;
 // pub mod day21;
 // pub mod day22;
-pub mod day23;
+// pub mod day23;
+pub mod day24;