FEATURE: Create concatenation function & indexing function.

Author: jbey251

lesson_11/arrays_java/arrays_app/src/main/java/com/codedifferently/lesson11/Lesson11.java

@@ -1,5 +1,6 @@
 package com.codedifferently.lesson11;
 
+import java.util.ArrayList;
 import java.util.List;
 
 public class Lesson11 {
@@ -9,14 +10,40 @@ public class Lesson11 {
    * https://leetcode.com/problems/concatenation-of-array
    */
   public int[] getConcatenation(int[] nums) {
-    return null;
+    int n = nums.length; // Puts length of nums case into n.
+    int[] ans = new int[2 * n]; // Declares ans as an array with 6 values.
+
+    // Puts whatever is placed on the index number in each num[i] position and copies it to the
+    // ans[i] position > depending on what [i] is at the time.
+    for (int i = 0; i < n; i++) {
+      ans[i] = nums[i];
+    }
+
+    // Same thing as the last one, but with the starting position being on whatever index n is on.
+    // In this case, it's starting at index 3, aka, position 4. This is where the concatenation part happens.
+    for (int i = 0; i < n; i++) {
+      ans[i + n] = nums[i];
+    }
+    // Side note...I'm not sure if this happens after the first 3 numbers have been added, during
+    // each loop, or after.
+
+    return ans;
   }
 
   /**
    * Provide the solution to LeetCode 2942 here:
    * https://leetcode.com/problems/find-words-containing-character/
    */
   public List<Integer> findWordsContaining(String[] words, char x) {
-    return null;
+    List<Integer> result = new ArrayList<>();
+
+    // Iterating through the array.
+    for (int i = 0; i < words.length; i++) { 
+      if (words[i].indexOf(x) != -1) { // If a particular index contains x, and it does not strictly equal -1 (aka, an index that doesn't exist)...
+        result.add(i); // Then append the index at the end of the list.
+      }
+    }
+
+    return result; // Return the index of x in an array.
   }
 }