From e6309177f361a4cd0396d742d8e39c328a051fbe Mon Sep 17 00:00:00 2001
From: William Perron <hey@wperron.io>
Date: Tue, 7 Mar 2023 09:42:06 -0500
Subject: [PATCH] add word scrambling (issue #290)

---
 Cargo.lock           | 72 ++++++++++++++++++++++++++++++++++++++++++++
 Cargo.toml           |  1 +
 scramble/Cargo.toml  |  9 ++++++
 scramble/src/main.rs | 38 +++++++++++++++++++++++
 4 files changed, 120 insertions(+)
 create mode 100644 scramble/Cargo.toml
 create mode 100644 scramble/src/main.rs

diff --git a/Cargo.lock b/Cargo.lock
index 1acaa6d..46139b2 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -6,6 +6,78 @@ version = 3
 name = "balance"
 version = "0.1.0"
 
+[[package]]
+name = "cfg-if"
+version = "1.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "baf1de4339761588bc0619e3cbc0120ee582ebb74b53b4efbf79117bd2da40fd"
+
+[[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 = "0.2.139"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "201de327520df007757c1f0adce6e827fe8562fbc28bfd9c15571c66ca1f5f79"
+
+[[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 = "repeated-groups"
 version = "0.1.0"
+
+[[package]]
+name = "scramble"
+version = "0.1.0"
+dependencies = [
+ "rand",
+]
+
+[[package]]
+name = "wasi"
+version = "0.11.0+wasi-snapshot-preview1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9c8d87e72b64a3b4db28d11ce29237c246188f4f51057d65a7eab63b7987e423"
diff --git a/Cargo.toml b/Cargo.toml
index d919de0..9ea4962 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -2,4 +2,5 @@
 members = [
   "balance",
   "repeated-groups",
+  "scramble",
 ]
diff --git a/scramble/Cargo.toml b/scramble/Cargo.toml
new file mode 100644
index 0000000..1b3db98
--- /dev/null
+++ b/scramble/Cargo.toml
@@ -0,0 +1,9 @@
+[package]
+name = "scramble"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+rand = "0.8.5"
diff --git a/scramble/src/main.rs b/scramble/src/main.rs
new file mode 100644
index 0000000..1731970
--- /dev/null
+++ b/scramble/src/main.rs
@@ -0,0 +1,38 @@
+use rand::seq::SliceRandom;
+
+/// If you mix up the order of letters in a word, many people can slitl raed and urenadnstd tehm. Write a function that
+/// takes an input sentence, and mixes up the insides of words (anything longer than 3 letters).
+///
+/// Example:
+///
+/// ```
+/// > scramble(["A quick brown fox jumped over the lazy dog."])
+/// > "A qciuk bwron fox jmepud oevr the lzay dog."
+/// ```
+
+fn main() {
+    let mut sentence = "A quick brown fox jumped over the lazy dog.".to_string();
+    scramble(&mut sentence);
+    println!("{}", sentence);
+}
+
+fn scramble(sentence: &mut String) {
+    let mut i = 0;
+    while i < sentence.len() {
+        if let Some(word_len) = sentence.get(i..).unwrap().find(' ') {
+            if word_len >= 4 {
+                let inner = sentence.get_mut(i + 1..i + word_len - 1).unwrap();
+
+                // shuffle it
+                let mut rng = rand::thread_rng();
+                unsafe {
+                    inner.as_bytes_mut().shuffle(&mut rng);
+                }
+            }
+
+            i = i + word_len + 1;
+        } else {
+            break;
+        }
+    }
+}