From bcaf81919cb889c1209c6d1e577b037047714c05 Mon Sep 17 00:00:00 2001
From: Adrian Mejia <adriansky@gmail.com>
Date: Tue, 28 Jul 2020 14:11:07 -0400
Subject: [PATCH] feat(book/arrays): add exercises

---
 book/content/part02/array.asc                | 46 +++++++++++++++++++-
 book/content/part02/linked-list.asc          |  4 ++
 lab/exercises/01-arrays/rotate-array-left.js | 15 +++++++
 lab/exercises/01-arrays/sum-arrays.js        | 13 ++++++
 4 files changed, 77 insertions(+), 1 deletion(-)
 create mode 100644 lab/exercises/01-arrays/rotate-array-left.js
 create mode 100644 lab/exercises/01-arrays/sum-arrays.js

diff --git a/book/content/part02/array.asc b/book/content/part02/array.asc
index 6c95d376..34cadf6a 100644
--- a/book/content/part02/array.asc
+++ b/book/content/part02/array.asc
@@ -7,7 +7,7 @@ endif::[]
 === Array
 (((Array)))
 (((Data Structures, Linear, Array)))
-Arrays are one of the most used data structures. You probably have used it a lot but are you aware of the runtimes of  `splice`, `shift`, `indexOf`  and other operations? In this chapter, we are going deeper into the most common operations and their runtimes.
+Arrays are one of the most used data structures. You probably have used it a lot but are you aware of the runtimes of `splice`, `shift`, `indexOf`  and other operations? In this chapter, we are going deeper into the most common operations and their runtimes.
 
 ==== Array  Basics
 
@@ -274,3 +274,47 @@ To sum up, the time complexity of an array is:
 | splice ^| O(n) | Insert and remove from anywhere.
 |===
 //end::table
+
+==== Array Exercises
+
+1) Implement an efficient algorithm that rotate an array `a` an `k` number of times.
+
+[source, javascript]
+----
+/**
+ * Rotate an array left by k number of times.
+ *
+ * @example
+ *    rotateLeft([1,2,3], 1); // [2,3,1]
+ *    rotateLeft([1,2,3,4,5], 4); // [5,1,2,3,4]
+ *
+ *    rotateLeft(Array(1e6).fill(1), 1e4); // <scale testing>
+ *
+ * @param a - The array
+ * @param k - The number of times the array is rotated
+ */
+function rotateLeft(a, k) {
+  // write you code and test with examples
+}
+----
+
+
+2) Implement an algorithm that takes two arrays of numbers and return a new array with the sum.
+
+[source, javascript]
+----
+/**
+ * Return the sum of two arrays as a new array.
+ *
+ * @example
+ *    sum([1,2,3], [1,1,1]); // [2,3,4]
+ *    sum([1], [9,9,9]); // [1,0,0,0]
+ *
+ * @param {number[]} a - Array of numbers.
+ * @param {number[]} b - Array of numbers.
+ * @returns {number[]} the sum array.
+ */
+function sum(a, b) {
+  // write you code and test with examples
+}
+----
diff --git a/book/content/part02/linked-list.asc b/book/content/part02/linked-list.asc
index 263caef3..6e3f3f98 100644
--- a/book/content/part02/linked-list.asc
+++ b/book/content/part02/linked-list.asc
@@ -285,3 +285,7 @@ Use a doubly linked list when:
 * You want to save some memory when dealing with possibly large data sets. Arrays pre-allocate a large chunk of contiguous memory on initialization. Lists are more “grow as you go”.
 
 For the next two linear data structures <<part02-linear-data-structures#stack>> and <<part02-linear-data-structures#queue>>, we are going to use a doubly linked list to implement them. We could use an array as well, but since inserting/deleting from the start performs better with linked-lists, we are going use that.
+
+==== Linked List Exercises
+
+1) Merge two sorted lists into one (and keep them sorted)
diff --git a/lab/exercises/01-arrays/rotate-array-left.js b/lab/exercises/01-arrays/rotate-array-left.js
new file mode 100644
index 00000000..88640b89
--- /dev/null
+++ b/lab/exercises/01-arrays/rotate-array-left.js
@@ -0,0 +1,15 @@
+/**
+ * Rotate an array left by k number of times.
+ *
+ * @example
+ *    rotateLeft([1,2,3], 1); // [2,3,1]
+ *    rotateLeft([1,2,3,4,5], 4); // [5,1,2,3,4]
+ *
+ *    rotateLeft(Array(1e6).fill(1), 1e4); // <scale testing>
+ *
+ * @param a - The array
+ * @param k - The number of times the array is rotated
+ */
+function rotateLeft(a, k) {
+  // write you code and test with examples
+}
diff --git a/lab/exercises/01-arrays/sum-arrays.js b/lab/exercises/01-arrays/sum-arrays.js
new file mode 100644
index 00000000..24d3576a
--- /dev/null
+++ b/lab/exercises/01-arrays/sum-arrays.js
@@ -0,0 +1,13 @@
+/**
+ * Return the sum of two arrays as a new array.
+ *
+ * @example
+ *    sum([1,2,3], [1,1,1]); // [2,3,4]
+ *    sum([1], [9,9,9]); // [1,0,0,0]
+ *
+ * @param {number[]} a - Array of numbers.
+ * @param {number[]} b - Array of numbers.
+ * @returns {number[]} the sum array.
+ */
+function sum(a, b) {
+}