Optimize the hell out of day02

Cargo.lock

@@ -25,6 +25,7 @@ dependencies = [
  "color-eyre",
  "criterion",
  "itertools 0.14.0",
+ "rayon",
  "test-log",
  "tracing",
  "tracing-error",
@@ -40,6 +41,15 @@ dependencies = [
  "memchr",
 ]
 
+[[package]]
+name = "alloca"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e5a7d05ea6aea7e9e64d25b9156ba2fee3fdd659e34e41063cd2fc7cd020d7f4"
+dependencies = [
+ "cc",
+]
+
 [[package]]
 name = "anes"
 version = "0.1.6"
@@ -129,6 +139,16 @@ version = "0.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "37b2a672a2cb129a2e41c10b1224bb368f9f37a2b16b612598138befd7b37eb5"
 
+[[package]]
+name = "cc"
+version = "1.2.48"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c481bdbf0ed3b892f6f806287d72acd515b352a4ec27a208489b8c1bc839633a"
+dependencies = [
+ "find-msvc-tools",
+ "shlex",
+]
+
 [[package]]
 name = "cfg-if"
 version = "1.0.4"
@@ -237,25 +257,24 @@ checksum = "b05b61dc5112cbb17e4b6cd61790d9845d13888356391624cbe7e41efeac1e75"
 
 [[package]]
 name = "criterion"
-version = "0.5.1"
+version = "0.8.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f2b12d017a929603d80db1831cd3a24082f8137ce19c69e6447f54f5fc8d692f"
+checksum = "a0dfe5e9e71bdcf4e4954f7d14da74d1cdb92a3a07686452d1509652684b1aab"
 dependencies = [
+ "alloca",
  "anes",
  "cast",
  "ciborium",
  "clap",
  "criterion-plot",
- "is-terminal",
+ "itertools 0.13.0",
- "itertools 0.10.5",
  "num-traits",
- "once_cell",
  "oorandom",
+ "page_size",
  "plotters",
  "rayon",
  "regex",
  "serde",
- "serde_derive",
  "serde_json",
  "tinytemplate",
  "walkdir",
@@ -263,12 +282,12 @@ dependencies = [
 
 [[package]]
 name = "criterion-plot"
-version = "0.5.0"
+version = "0.8.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6b50826342786a51a89e2da3a28f1c32b06e387201bc2d19791f622c673706b1"
+checksum = "5de36c2bee19fba779808f92bf5d9b0fa5a40095c277aba10c458a12b35d21d6"
 dependencies = [
  "cast",
- "itertools 0.10.5",
+ "itertools 0.13.0",
 ]
 
 [[package]]
@@ -318,6 +337,12 @@ dependencies = [
  "once_cell",
 ]
 
+[[package]]
+name = "find-msvc-tools"
+version = "0.1.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3a3076410a55c90011c298b04d0cfa770b00fa04e1e3c97d3f6c9de105a03844"
+
 [[package]]
 name = "gimli"
 version = "0.32.3"
@@ -341,29 +366,12 @@ version = "0.5.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "2304e00983f87ffb38b55b444b5e3b60a884b5d30c0fca7d82fe33449bbe55ea"
 
-[[package]]
-name = "hermit-abi"
-version = "0.5.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "fc0fef456e4baa96da950455cd02c081ca953b141298e41db3fc7e36b1da849c"
-
 [[package]]
 name = "indenter"
 version = "0.3.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "964de6e86d545b246d84badc0fef527924ace5134f30641c203ef52ba83f58d5"
 
-[[package]]
-name = "is-terminal"
-version = "0.4.17"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3640c1c38b8e4e43584d8df18be5fc6b0aa314ce6ebf51b53313d4306cca8e46"
-dependencies = [
- "hermit-abi",
- "libc",
- "windows-sys 0.61.2",
-]
-
 [[package]]
 name = "is_terminal_polyfill"
 version = "1.70.2"
@@ -372,9 +380,9 @@ checksum = "a6cb138bb79a146c1bd460005623e142ef0181e3d0219cb493e02f7d08a35695"
 
 [[package]]
 name = "itertools"
-version = "0.10.5"
+version = "0.13.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b0fd2260e829bddf4cb6ea802289de2f86d6a7a690192fbe91b3f46e0f2c8473"
+checksum = "413ee7dfc52ee1a4949ceeb7dbc8a33f2d6c088194d9f922fb8318faf1f01186"
 dependencies = [
  "either",
 ]
@@ -497,6 +505,16 @@ version = "4.2.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9c6901729fa79e91a0913333229e9ca5dc725089d1c363b2f4b4760709dc4a52"
 
+[[package]]
+name = "page_size"
+version = "0.6.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "30d5b2194ed13191c1999ae0704b7839fb18384fa22e49b57eeaa97d79ce40da"
+dependencies = [
+ "libc",
+ "winapi",
+]
+
 [[package]]
 name = "pin-project-lite"
 version = "0.2.16"
@@ -677,6 +695,12 @@ dependencies = [
  "lazy_static",
 ]
 
+[[package]]
+name = "shlex"
+version = "1.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0fda2ff0d084019ba4d7c6f371c95d8fd75ce3524c3cb8fb653a3023f6323e64"
+
 [[package]]
 name = "smallvec"
 version = "1.15.1"
@@ -894,6 +918,22 @@ dependencies = [
  "wasm-bindgen",
 ]
 
+[[package]]
+name = "winapi"
+version = "0.3.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5c839a674fcd7a98952e593242ea400abe93992746761e38641405d28b00f419"
+dependencies = [
+ "winapi-i686-pc-windows-gnu",
+ "winapi-x86_64-pc-windows-gnu",
+]
+
+[[package]]
+name = "winapi-i686-pc-windows-gnu"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ac3b87c63620426dd9b991e5ce0329eff545bccbbb34f3be09ff6fb6ab51b7b6"
+
 [[package]]
 name = "winapi-util"
 version = "0.1.11"
@@ -903,6 +943,12 @@ dependencies = [
  "windows-sys 0.61.2",
 ]
 
+[[package]]
+name = "winapi-x86_64-pc-windows-gnu"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "712e227841d057c1ee1cd2fb22fa7e5a5461ae8e48fa2ca79ec42cfc1931183f"
+
 [[package]]
 name = "windows-link"
 version = "0.2.1"

Cargo.toml

@@ -7,12 +7,13 @@ edition = "2024"
 clap = { version = "4.5", features = ["derive"] }
 color-eyre = "0.6"
 itertools = "0.14"
+rayon = "1.11"
 tracing = "0.1"
 tracing-error = "0.2"
 tracing-subscriber = { version = "0.3", features = ["env-filter"] }
 
 [dev-dependencies]
-criterion = "0.5.1"
+criterion = "0.8.0"
 test-log = { version = "0.2", default-features = false, features = ["trace"] }
 
 # Improve perf on debug builds: https://docs.rs/color-eyre/latest/color_eyre/#improving-perf-on-debug-builds

README.md

@@ -33,4 +33,4 @@ Timings are given as: [lower-bound **best-estimate** upper-bound]
 | Day | Part 1 | Part 2 |
 |-----|--------|--------|
 | 01  | [101.34 µs **101.95 µs** 102.61 µs] | [105.90 µs **106.40 µs** 106.95 µs] |
-| 02  | [165.59 ms **166.60 ms** 167.65 ms] | [184.17 ms **185.25 ms** 186.42 ms] |
+| 02  | [2.0990 ms **2.1113 ms** 2.1236 ms] | [2.0954 ms **2.1055 ms** 2.1157 ms] |

src/day02/mod.rs

@@ -2,9 +2,9 @@ use std::{fmt::Display, str::FromStr};
 
 use color_eyre::{
     Result,
-    eyre::{Error, OptionExt, eyre},
+    eyre::{Error, eyre},
 };
-use itertools::Itertools;
+use rayon::prelude::*;
 use tracing::{debug, debug_span, instrument};
 
 pub const INPUT: &str = include_str!("input/input.txt");
@@ -50,54 +50,34 @@ impl Iterator for ProductRange {
     }
 }
 
-fn is_valid_product_id(id: i64) -> Result<bool> {
-    let digits: Vec<u32> = id
-        .to_string()
-        .chars()
-        .map(|c| {
-            c.to_digit(10)
-                .ok_or_eyre("Invalid product id: contains a non-decimal digit")
-        })
-        .collect::<Result<Vec<u32>>>()?;
-    if digits.len() % 2 != 0 {
-        return Ok(true);
-    }
-    Ok(digits[..digits.len() / 2] != digits[digits.len() / 2..])
-}
-
-fn is_valid_product_id2(id: i64) -> Result<bool> {
-    let digits: Vec<u32> = id
-        .to_string()
-        .chars()
-        .map(|c| {
-            c.to_digit(10)
-                .ok_or_eyre("Invalid product id: contains a non-decimal digit")
-        })
-        .collect::<Result<Vec<u32>>>()?;
-    let mut chunk_size = digits.len() / 2;
-    loop {
-        if chunk_size == 0 {
-            break;
-        }
-        if digits
-            .chunks(chunk_size)
-            .tuple_windows()
-            .all(|(a, b)| a == b)
-        {
-            return Ok(false);
-        }
-        chunk_size -= 1;
-    }
-    Ok(true)
-}
-
 impl ProductRange {
     fn invalid_ids(self) -> Result<Vec<i64>> {
-        let mut invalid_ids = vec![];
+        let start = *self.0.start();
+        let end = *self.0.end();
 
-        for id in self {
+        let mut invalid_ids = Vec::new();
-            if !is_valid_product_id(id)? {
+
-                invalid_ids.push(id);
+        // Determine digit ranges we need to check
+        let start_digits = if start == 0 { 1 } else { start.ilog10() + 1 };
+        let end_digits = if end == 0 { 1 } else { end.ilog10() + 1 };
+
+        for num_digits in start_digits..=end_digits {
+            // Skip odd digit counts - they're all valid
+            if num_digits % 2 != 0 {
+                continue;
+            }
+
+            let half_digits = num_digits / 2;
+            let half_min = 10_i64.pow(half_digits - 1);
+            let half_max = 10_i64.pow(half_digits) - 1;
+            let multiplier = 10_i64.pow(half_digits) + 1; // Pre-calculate: half * multiplier = AABB pattern
+
+            // Generate all patterns where first half == second half
+            for half in half_min..=half_max {
+                let id = half * multiplier;
+                if id >= start && id <= end {
+                    invalid_ids.push(id);
+                }
             }
         }
 
@@ -106,14 +86,51 @@ impl ProductRange {
     }
 
     fn invalid_ids2(self) -> Result<Vec<i64>> {
-        let mut invalid_ids = vec![];
+        let start = *self.0.start();
+        let end = *self.0.end();
 
-        for id in self {
+        let mut invalid_ids = std::collections::HashSet::new();
-            if !is_valid_product_id2(id)? {
+
-                invalid_ids.push(id);
+        // Determine digit ranges we need to check
+        let start_digits = if start == 0 { 1 } else { start.ilog10() + 1 };
+        let end_digits = if end == 0 { 1 } else { end.ilog10() + 1 };
+
+        for num_digits in start_digits..=end_digits {
+            // Try all possible chunk sizes that divide evenly
+            for chunk_size in 1..=num_digits / 2 {
+                if num_digits % chunk_size != 0 {
+                    continue;
+                }
+
+                let num_chunks = num_digits / chunk_size;
+                if num_chunks < 2 {
+                    continue;
+                }
+
+                // Generate all possible chunk patterns
+                let chunk_min = 10_i64.pow(chunk_size - 1);
+                let chunk_max = 10_i64.pow(chunk_size) - 1;
+                let chunk_power = 10_i64.pow(chunk_size);
+
+                // Calculate multiplier for repeating pattern
+                // For ABCABC: chunk * (10^6 + 10^3 + 1) = chunk * 1001001
+                let mut multiplier = 0_i64;
+                for i in 0..num_chunks {
+                    multiplier += chunk_power.pow(i);
+                }
+
+                for chunk in chunk_min..=chunk_max {
+                    let id = chunk * multiplier;
+
+                    if id >= start && id <= end {
+                        invalid_ids.insert(id);
+                    }
+                }
             }
         }
 
+        let invalid_ids: Vec<i64> = invalid_ids.into_iter().collect();
+
         debug!("Invalid IDs: {:?}", &invalid_ids);
         Ok(invalid_ids)
     }
@@ -121,24 +138,32 @@ impl ProductRange {
 
 #[instrument(skip(input))]
 pub fn part1(input: &str) -> Result<i64> {
-    let mut total_invalid = 0;
+    input
-    for range in input.trim().split(',') {
+        .trim()
-        let _span = debug_span!("range", range = %range).entered();
+        .split(',')
-        let range: ProductRange = range.parse()?;
+        .collect::<Vec<_>>()
-        total_invalid += range.invalid_ids()?.iter().sum::<i64>();
+        .into_par_iter()
-    }
+        .map(|range| {
-    Ok(total_invalid)
+            let _span = debug_span!("range", range = %range).entered();
+            let range: ProductRange = range.parse()?;
+            Ok(range.invalid_ids()?.iter().sum::<i64>())
+        })
+        .sum()
 }
 
 #[instrument(skip(input))]
 pub fn part2(input: &str) -> Result<i64> {
-    let mut total_invalid = 0;
+    input
-    for range in input.trim().split(',') {
+        .trim()
-        let _span = debug_span!("range", range = %range).entered();
+        .split(',')
-        let range: ProductRange = range.parse()?;
+        .collect::<Vec<_>>()
-        total_invalid += range.invalid_ids2()?.iter().sum::<i64>();
+        .into_par_iter()
-    }
+        .map(|range| {
-    Ok(total_invalid)
+            let _span = debug_span!("range", range = %range).entered();
+            let range: ProductRange = range.parse()?;
+            Ok(range.invalid_ids2()?.iter().sum::<i64>())
+        })
+        .sum()
 }
 
 #[cfg(test)]