Parse input from stdin, improve output

Cargo.lock

@@ -2,12 +2,49 @@
 # It is not intended for manual editing.
 version = 3
 
+[[package]]
+name = "anyhow"
+version = "1.0.82"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f538837af36e6f6a9be0faa67f9a314f8119e4e4b5867c6ab40ed60360142519"
+
 [[package]]
 name = "cfg-if"
 version = "1.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "baf1de4339761588bc0619e3cbc0120ee582ebb74b53b4efbf79117bd2da40fd"
 
+[[package]]
+name = "crossbeam-deque"
+version = "0.8.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "613f8cc01fe9cf1a3eb3d7f488fd2fa8388403e97039e2f73692932e291a770d"
+dependencies = [
+ "crossbeam-epoch",
+ "crossbeam-utils",
+]
+
+[[package]]
+name = "crossbeam-epoch"
+version = "0.9.18"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5b82ac4a3c2ca9c3460964f020e1402edd5753411d7737aa39c3714ad1b5420e"
+dependencies = [
+ "crossbeam-utils",
+]
+
+[[package]]
+name = "crossbeam-utils"
+version = "0.8.19"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "248e3bacc7dc6baa3b21e405ee045c3047101a49145e7e9eca583ab4c2ca5345"
+
+[[package]]
+name = "either"
+version = "1.11.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a47c1c47d2f5964e29c61246e81db715514cd532db6b5116a25ea3c03d6780a2"
+
 [[package]]
 name = "getrandom"
 version = "0.2.14"
@@ -29,7 +66,9 @@ checksum = "ae743338b92ff9146ce83992f766a31066a91a8c84a45e0e9f21e7cf6de6d346"
 name = "lotto"
 version = "0.1.0"
 dependencies = [
+ "anyhow",
  "rand",
+ "rayon",
 ]
 
 [[package]]
@@ -68,6 +107,26 @@ dependencies = [
  "getrandom",
 ]
 
+[[package]]
+name = "rayon"
+version = "1.10.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b418a60154510ca1a002a752ca9714984e21e4241e804d32555251faf8b78ffa"
+dependencies = [
+ "either",
+ "rayon-core",
+]
+
+[[package]]
+name = "rayon-core"
+version = "1.12.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1465873a3dfdaa8ae7cb14b4383657caab0b3e8a0aa9ae8e04b044854c8dfce2"
+dependencies = [
+ "crossbeam-deque",
+ "crossbeam-utils",
+]
+
 [[package]]
 name = "wasi"
 version = "0.11.0+wasi-snapshot-preview1"

Cargo.toml

@@ -6,4 +6,6 @@ edition = "2021"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
+anyhow = "1.0.82"
 rand = "0.8.5"
+rayon = "1.10.0"

src/main.rs

@@ -1,34 +1,37 @@
-use rand::Rng;
-use std::time::Instant;
+use anyhow::anyhow;
+use std::io::BufRead;
+use std::{
+    io::{stdin, BufReader},
+    time::Instant,
+};
 
 type Ticket = [u8; 5];
 const NUM_ENTRIES: usize = 10_000_000;
 
-// println!("char: {}", rand::random::<char>());
+fn ticket_from_str(s: &str) -> Result<Ticket, anyhow::Error> {
+    let mut nums = s.split(" ").take(5).map(|s| s.parse::<u8>()).into_iter();
 
-fn gen_num() -> u8 {
-    rand::thread_rng().gen_range(0..90)
+    let num1 = nums.next();
+    let num2 = nums.next();
+    let num3 = nums.next();
+    let num4 = nums.next();
+    let num5 = nums.next();
+    if num1.is_none() || num2.is_none() || num3.is_none() || num4.is_none() || num5.is_none() {
+        return Err(anyhow!("invalid lotto number"));
+    }
+    let r = [
+        num1.unwrap()?,
+        num2.unwrap()?,
+        num3.unwrap()?,
+        num4.unwrap()?,
+        num5.unwrap()?,
+    ];
+
+    if r[0] > 90 || r[1] > 90 || r[2] > 90 || r[3] > 90 || r[4] > 90 {
+        return Err(anyhow!("lotto number too high"));
     }
 
-fn gen_ticket() -> Ticket {
-    let num1 = gen_num();
-    let mut num2: u8 = gen_num();
-    while num2 == num1 {
-        num2 = gen_num()
-    }
-    let mut num3: u8 = gen_num();
-    while num3 == num1 || num3 == num2 {
-        num3 = gen_num()
-    }
-    let mut num4: u8 = gen_num();
-    while num4 == num1 || num4 == num2 || num4 == num3 {
-        num4 = gen_num()
-    }
-    let mut num5: u8 = gen_num();
-    while num5 == num1 || num5 == num2 || num5 == num3 || num5 == num4 {
-        num5 = gen_num()
-    }
-    [num1, num2, num3, num4, num5]
+    Ok(r)
 }
 
 fn num_matches(t1: Ticket, t2: Ticket) -> usize {
@@ -43,17 +46,27 @@ fn num_matches(t1: Ticket, t2: Ticket) -> usize {
     result
 }
 
-fn main() {
-    println!("Generating entries");
-    let mut entries: Vec<Ticket> = Vec::with_capacity(NUM_ENTRIES);
-    for _ in 0..NUM_ENTRIES {
-        entries.push(gen_ticket());
+fn main() -> Result<(), anyhow::Error> {
+    println!("Parsing entries");
+
+    let reader = BufReader::new(stdin());
+    let mut entries = Vec::with_capacity(NUM_ENTRIES);
+
+    for line in reader.lines() {
+        match line {
+            Ok(l) => match ticket_from_str(&l) {
+                Ok(n) => entries.push(n),
+                Err(_) => {} // noop
+            },
+            Err(_) => break,
         }
-    let winning = gen_ticket();
+    }
+    println!("{} entries parsed from stdin", entries.len());
+
+    let winning = [68, 81, 40, 34, 85];
 
     let start = Instant::now();
-
-    println!("Counting winners...");
+    println!("Counting winners... (timer started)");
     let mut winners: [usize; 6] = [0, 0, 0, 0, 0, 0];
 
     for n in entries {
@@ -61,6 +74,7 @@ fn main() {
         winners[num_winning] += 1
     }
 
+    println!("Done counting winners (timer stopped)");
     let duration = start.elapsed();
 
     println!(
@@ -68,4 +82,6 @@ fn main() {
         winners,
         duration.subsec_millis()
     );
+
+    Ok(())
 }