Add secret handshake exercise (#1626)

Author: dem4ron

config.json

@@ -1466,6 +1466,15 @@
           "unsafe"
         ]
       },
+      {
+        "slug": "secret-handshake",
+        "name": "Secret Handshake",
+        "uuid": "8c044530-9deb-4ff7-a638-98d6c05ebbb8",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 4,
+        "topics": []
+      },
       {
         "slug": "hexadecimal",
         "name": "Hexadecimal",

exercises/practice/secret-handshake/.docs/instructions.md

@@ -0,0 +1,24 @@
+# Instructions
+
+> There are 10 types of people in the world: Those who understand
+> binary, and those who don't.
+
+You and your fellow cohort of those in the "know" when it comes to binary decide to come up with a secret "handshake".
+
+```text
+00001 = wink
+00010 = double blink
+00100 = close your eyes
+01000 = jump
+
+10000 = Reverse the order of the operations in the secret handshake.
+```
+
+Given a decimal number, convert it to the appropriate sequence of events for a secret handshake.
+
+Here's a couple of examples:
+
+Given the decimal input 3, the function would return the array ["wink", "double blink"] because the decimal number 3 is 2+1 in powers of two and thus `11` in binary.
+
+Let's now examine the input 19 which is 16+2+1 in powers of two and thus `10011` in binary.
+Recalling that the addition of 16 (`10000` in binary) reverses an array and that we already know what array is returned given input 3, the array returned for input 19 is ["double blink", "wink"].

exercises/practice/secret-handshake/.gitignore

@@ -0,0 +1,8 @@
+# Generated by Cargo
+# will have compiled files and executables
+/target/
+**/*.rs.bk
+
+# Remove Cargo.lock from gitignore if creating an executable, leave it for libraries
+# More information here http://doc.crates.io/guide.html#cargotoml-vs-cargolock
+Cargo.lock

exercises/practice/secret-handshake/.meta/config.json

@@ -0,0 +1,20 @@
+{
+  "authors": [
+    "dem4ron"
+  ],
+  "files": {
+    "solution": [
+      "src/lib.rs",
+      "Cargo.toml"
+    ],
+    "test": [
+      "tests/secret-handshake.rs"
+    ],
+    "example": [
+      ".meta/example.rs"
+    ]
+  },
+  "blurb": "Given a decimal number, convert it to the appropriate sequence of events for a secret handshake.",
+  "source": "Bert, in Mary Poppins",
+  "source_url": "https://www.imdb.com/title/tt0058331/quotes/qt0437047"
+}

exercises/practice/secret-handshake/.meta/example.rs

@@ -0,0 +1,16 @@
+const ACTIONS: [&str; 4] = ["wink", "double blink", "close your eyes", "jump"];
+
+pub fn actions(n: u8) -> Vec<&'static str> {
+    let result: Vec<&str> = ACTIONS
+        .iter()
+        .enumerate()
+        .filter(|(i, _)| (1u8 << *i) & n != 0)
+        .map(|(_, &c)| c)
+        .collect();
+
+    if n & 16 != 0 {
+        result.into_iter().rev().collect()
+    } else {
+        result
+    }
+}

exercises/practice/secret-handshake/.meta/tests.toml

@@ -0,0 +1,43 @@
+# This is an auto-generated file.
+#
+# Regenerating this file via `configlet sync` will:
+# - Recreate every `description` key/value pair
+# - Recreate every `reimplements` key/value pair, where they exist in problem-specifications
+# - Remove any `include = true` key/value pair (an omitted `include` key implies inclusion)
+# - Preserve any other key/value pair
+#
+# As user-added comments (using the # character) will be removed when this file
+# is regenerated, comments can be added via a `comment` key.
+
+[b8496fbd-6778-468c-8054-648d03c4bb23]
+description = "wink for 1"
+
+[83ec6c58-81a9-4fd1-bfaf-0160514fc0e3]
+description = "double blink for 10"
+
+[0e20e466-3519-4134-8082-5639d85fef71]
+description = "close your eyes for 100"
+
+[b339ddbb-88b7-4b7d-9b19-4134030d9ac0]
+description = "jump for 1000"
+
+[40499fb4-e60c-43d7-8b98-0de3ca44e0eb]
+description = "combine two actions"
+
+[9730cdd5-ef27-494b-afd3-5c91ad6c3d9d]
+description = "reverse two actions"
+
+[0b828205-51ca-45cd-90d5-f2506013f25f]
+description = "reversing one action gives the same action"
+
+[9949e2ac-6c9c-4330-b685-2089ab28b05f]
+description = "reversing no actions still gives no actions"
+
+[23fdca98-676b-4848-970d-cfed7be39f81]
+description = "all possible actions"
+
+[ae8fe006-d910-4d6f-be00-54b7c3799e79]
+description = "reverse all possible actions"
+
+[3d36da37-b31f-4cdb-a396-d93a2ee1c4a5]
+description = "do nothing for zero"

exercises/practice/secret-handshake/Cargo.toml

@@ -0,0 +1,4 @@
+[package]
+edition = "2021"
+name = "secret-handshake"
+version = "1.1.0"

exercises/practice/secret-handshake/src/lib.rs

@@ -0,0 +1,3 @@
+pub fn actions(n: u8) -> Vec<&'static str> {
+    unimplemented!("What is the secret handshake for {n}?")
+}

exercises/practice/secret-handshake/tests/secret-handshake.rs

@@ -0,0 +1,72 @@
+use secret_handshake::*;
+
+#[test]
+fn wink_for_1() {
+    assert_eq!(actions(1), vec!["wink"])
+}
+
+#[test]
+#[ignore]
+fn double_blink_for_10() {
+    assert_eq!(actions(2), vec!["double blink"])
+}
+
+#[test]
+#[ignore]
+fn close_your_eyes_for_100() {
+    assert_eq!(actions(4), vec!["close your eyes"])
+}
+
+#[test]
+#[ignore]
+fn jump_for_1000() {
+    assert_eq!(actions(8), vec!["jump"])
+}
+
+#[test]
+#[ignore]
+fn combine_two_actions() {
+    assert_eq!(actions(3), vec!["wink", "double blink"])
+}
+
+#[test]
+#[ignore]
+fn reverse_two_actions() {
+    assert_eq!(actions(19), vec!["double blink", "wink"])
+}
+
+#[test]
+#[ignore]
+fn reversing_one_action_gives_the_same_action() {
+    assert_eq!(actions(24), vec!["jump"])
+}
+
+#[test]
+#[ignore]
+fn reversing_no_actions_still_gives_no_actions() {
+    assert_eq!(actions(16), Vec::<&'static str>::new())
+}
+
+#[test]
+#[ignore]
+fn all_possible_actions() {
+    assert_eq!(
+        actions(15),
+        vec!["wink", "double blink", "close your eyes", "jump"]
+    )
+}
+
+#[test]
+#[ignore]
+fn reverse_all_possible_actions() {
+    assert_eq!(
+        actions(31),
+        vec!["jump", "close your eyes", "double blink", "wink"]
+    )
+}
+
+#[test]
+#[ignore]
+fn do_nothing_for_zero() {
+    assert_eq!(actions(0), Vec::<&'static str>::new())
+}