Generate larger problems for day01

Cargo.lock

@@ -2,6 +2,12 @@
 # It is not intended for manual editing.
 version = 3
 
+[[package]]
+name = "cfg-if"
+version = "1.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "baf1de4339761588bc0619e3cbc0120ee582ebb74b53b4efbf79117bd2da40fd"
+
 [[package]]
 name = "day01"
 version = "0.1.0"
@@ -9,6 +15,9 @@ version = "0.1.0"
 [[package]]
 name = "day01-gen-problem"
 version = "0.1.0"
+dependencies = [
+ "rand",
+]
 
 [[package]]
 name = "day02"
@@ -101,3 +110,62 @@ version = "0.1.0"
 [[package]]
 name = "day24"
 version = "0.1.0"
+
+[[package]]
+name = "getrandom"
+version = "0.2.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c05aeb6a22b8f62540c194aac980f2115af067bfe15a0734d7277a768d396b31"
+dependencies = [
+ "cfg-if",
+ "libc",
+ "wasi",
+]
+
+[[package]]
+name = "libc"
+version = "0.2.137"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "fc7fcc620a3bff7cdd7a365be3376c97191aeaccc2a603e600951e452615bf89"
+
+[[package]]
+name = "ppv-lite86"
+version = "0.2.17"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5b40af805b3121feab8a3c29f04d8ad262fa8e0561883e7653e024ae4479e6de"
+
+[[package]]
+name = "rand"
+version = "0.8.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "34af8d1a0e25924bc5b7c43c079c942339d8f0a8b57c39049bef581b46327404"
+dependencies = [
+ "libc",
+ "rand_chacha",
+ "rand_core",
+]
+
+[[package]]
+name = "rand_chacha"
+version = "0.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e6c10a63a0fa32252be49d21e7709d4d4baf8d231c2dbce1eaa8141b9b127d88"
+dependencies = [
+ "ppv-lite86",
+ "rand_core",
+]
+
+[[package]]
+name = "rand_core"
+version = "0.6.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ec0be4795e2f6a28069bec0b5ff3e2ac9bafc99e6a9a7dc3547996c5c816922c"
+dependencies = [
+ "getrandom",
+]
+
+[[package]]
+name = "wasi"
+version = "0.11.0+wasi-snapshot-preview1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9c8d87e72b64a3b4db28d11ce29237c246188f4f51057d65a7eab63b7987e423"

day01-gen-problem/Cargo.toml

@@ -8,3 +8,4 @@ build = true
 app = true
 
 [dependencies]
+rand = "0.8.5"

day01-gen-problem/src/main.rs

@@ -1,3 +1,30 @@
+use std::{fs::File, io::BufWriter, io::Write};
+
+use rand::Rng;
+
+const PERCENT_NONE: f32 = 0.1;
+const LINE_COUNT: usize = 50_000_000;
+const MAX_CALORY: usize = 30_000;
+
 fn main() {
-    println!("Hello, world!");
+    let outfile = ::std::env::args()
+        .skip(1)
+        .next()
+        .expect("Output file as first parameter");
+    let mut outfile = BufWriter::new(File::create(outfile).expect("Can write outfile"));
+    let mut rng = rand::thread_rng();
+    (0..LINE_COUNT)
+        .map(|_| {
+            if rng.gen::<f32>() < PERCENT_NONE {
+                None
+            } else {
+                Some(rng.gen_range(0..MAX_CALORY))
+            }
+        })
+        .map(|opt| match opt {
+            Some(cal) => format!("{cal}\n"),
+            None => String::from("\n"),
+        })
+        .for_each(|line| write!(outfile, "{line}").expect("Writing works"));
+    outfile.flush().expect("Flushing works");
 }