reverse output linked list (examplehub#130)

realDuYuanChao · github-actions · web-flow · commit 97c39c691762 · 2021-07-03T09:04:22.000+08:00
* delete target element of singly linkedlist

* reverse output linked-list

* Formatted with Google Java Formatter

Co-authored-by: github-actions &lt;${GITHUB_ACTOR}@users.noreply.github.com&gt;
diff --git a/src/main/java/com/examplehub/datastructures/linkedlist/ReverseOutputLinkedList.java b/src/main/java/com/examplehub/datastructures/linkedlist/ReverseOutputLinkedList.java
@@ -0,0 +1,34 @@
+package com.examplehub.datastructures.linkedlist;
+
+import com.examplehub.leetcode.ListNode;
+import java.util.Stack;
+import java.util.StringJoiner;
+
+public class ReverseOutputLinkedList<E> {
+  private static StringJoiner output1 = new StringJoiner("->");
+  private static StringJoiner output2 = new StringJoiner("->");
+
+  public static String solution1(ListNode head) {
+    Stack stack = new Stack();
+    while (head != null) {
+      stack.add(head.val);
+      head = head.next;
+    }
+    while (!stack.isEmpty()) {
+      output1.add(stack.pop().toString());
+    }
+    return output1.toString();
+  }
+
+  public static String solution2(ListNode head) {
+    reverseOutputReverse(head);
+    return output2.toString();
+  }
+
+  public static void reverseOutputReverse(ListNode head) {
+    if (head != null) {
+      reverseOutputReverse(head.next);
+      output2.add(head.val + "");
+    }
+  }
+}
diff --git a/src/test/java/com/examplehub/datastructures/linkedlist/ReverseOutputLinkedListTest.java b/src/test/java/com/examplehub/datastructures/linkedlist/ReverseOutputLinkedListTest.java
@@ -0,0 +1,21 @@
+package com.examplehub.datastructures.linkedlist;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+import com.examplehub.leetcode.ListNode;
+import com.examplehub.utils.NodeUtils;
+import org.junit.jupiter.api.Test;
+
+class ReverseOutputLinkedListTest {
+  @Test
+  void testSolution1() {
+    ListNode head = NodeUtils.makeList(1, 2, 3, 4, 5);
+    assertEquals("5->4->3->2->1", ReverseOutputLinkedList.solution1(head));
+  }
+
+  @Test
+  void testSolution2() {
+    ListNode head = NodeUtils.makeList(1, 2, 3, 4, 5);
+    assertEquals("5->4->3->2->1", ReverseOutputLinkedList.solution2(head));
+  }
+}
