Add YT links. Fix comment in QueueUsing2StacksTest a bit

Author: andrei-punko

src/main/java/by/andd3dfx/collections/QueueUsing2Stacks.java

@@ -37,6 +37,8 @@
  *   myQueue.pop();     // return 1, queue is [2]
  *   myQueue.empty();   // return false
  * </pre>
+ *
+ * @see <a href="https://youtu.be/VlG_4iOE9MY">Video solution</a>
  */
 public class QueueUsing2Stacks {
 

src/main/java/by/andd3dfx/string/FirstUniqueCharacterInString.java

@@ -21,6 +21,8 @@
  * Input: s = "aabb"
  * Output: -1
  * </pre>
+ *
+ * @see <a href="https://youtu.be/Xg5ztSmpl-0">Video solution</a>
  */
 public class FirstUniqueCharacterInString {
 
@@ -33,11 +35,13 @@ public static int firstUniqChar(String s) {
                 map.put(ch, 1);
             }
         }
+
         for (var entry : map.entrySet()) {
             if (entry.getValue() == 1) {
                 return s.indexOf(entry.getKey());
             }
         }
+
         return -1;
     }
 }

src/test/java/by/andd3dfx/collections/QueueUsing2StacksTest.java

@@ -14,7 +14,7 @@ public void testQueue() {
         queue.push(3);      // queue is [1 2 3] (leftmost is front of the queue)
         assertThat(queue.peek()).isEqualTo(1);  // return 1
         assertThat(queue.pop()).isEqualTo(1);   // return 1, queue is [2 3]
-        assertThat(queue.pop()).isEqualTo(2);   // return 1, queue is [3]
+        assertThat(queue.pop()).isEqualTo(2);   // return 2, queue is [3]
         assertThat(queue.peek()).isEqualTo(3);  // return 3
         assertThat(queue.empty()).isFalse();
         assertThat(queue.pop()).isEqualTo(3);   // return 3, queue is []