feat: implemented LeetCode 1929, 2942

Author: XavierCruz5106

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

@@ -1,22 +1,34 @@
 package com.codedifferently.lesson11;
 
+import java.util.ArrayList;
 import java.util.List;
 
+
 public class Lesson11 {
 
   /**
    * Provide the solution to LeetCode 1929 here:
    * https://leetcode.com/problems/concatenation-of-array
    */
   public int[] getConcatenation(int[] nums) {
-    return null;
+    int [] ans = new int[nums.length * 2];
+    System.arraycopy(nums, 0, ans, 0, nums.length);
+    System.arraycopy(nums, 0, ans, nums.length, nums.length);
+    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;
+    ArrayList<Integer> out = new ArrayList<>();
+    for(int i = 0; i<words.length; i++){
+      if (words[i].indexOf(x) != -1){
+        out.add(i);
+      }
+    }
+
+    return out;
   }
 }