chore: implemented leetCode functions in Lesson11 file

Author: mercedes-mathews

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 +10,28 @@ public class Lesson11 {
    * https://leetcode.com/problems/concatenation-of-array
    */
   public int[] getConcatenation(int[] nums) {
-    return null;
+    int[] finalArr = new int[nums.length * 2];
+    for (int i = 0; i < nums.length; i++) {
+      finalArr[i] = nums[i];
+      finalArr[i + nums.length] = nums[i];
+    }
+
+    return finalArr;
   }
 
   /**
    * 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;
+    var results = new ArrayList<Integer>();
+    var ch = String.valueOf(x);
+    for (int i = 0; i < words.length; i++) {
+      if (words[i].contains(ch)) {
+        results.add(i);
+      }
+    }
+
+    return results;
   }
 }