refactor 101

fishercoder1534 · fishercoder1534 · commit 5b7b8b4101e0 · 2021-09-23T10:19:10.000-07:00
diff --git a/src/main/java/com/fishercoder/solutions/_101.java b/src/main/java/com/fishercoder/solutions/_101.java
@@ -18,4 +18,29 @@ private boolean isSymmetric(TreeNode left, TreeNode right) {
             return left.val == right.val && isSymmetric(left.left, right.right) && isSymmetric(left.right, right.left);
         }
     }
+
+    public static class Solution2 {
+        /**
+         * The same as the above solution, just a bit more verbose.
+         */
+        public boolean isSymmetric(TreeNode root) {
+            if (root == null) {
+                return true;
+            }
+            return isSymmetric(root.left, root.right);
+        }
+
+        private boolean isSymmetric(TreeNode left, TreeNode right) {
+            if (left == null && right == null) {
+                return true;
+            } else if (left == null || right == null) {
+                return false;
+            }
+            if (left.val == right.val) {
+                return isSymmetric(left.left, right.right) && isSymmetric(left.right, right.left);
+            } else {
+                return false;
+            }
+        }
+    }
 }
diff --git a/src/test/java/com/fishercoder/_101Test.java b/src/test/java/com/fishercoder/_101Test.java
@@ -3,30 +3,36 @@
 import com.fishercoder.common.classes.TreeNode;
 import com.fishercoder.common.utils.TreeUtils;
 import com.fishercoder.solutions._101;
+
 import java.util.Arrays;
+
 import org.junit.BeforeClass;
 import org.junit.Test;
 
 import static org.junit.Assert.assertEquals;
 
 public class _101Test {
-  private static _101.Solution1 solution1;
-  private static TreeNode root;
-
-  @BeforeClass
-  public static void setup() {
-    solution1 = new _101.Solution1();
-  }
-
-  @Test
-  public void test1() {
-    root = TreeUtils.constructBinaryTree(Arrays.asList(1, 2, 2, 3, 4, 4, 3));
-    assertEquals(true, solution1.isSymmetric(root));
-  }
-
-  @Test
-  public void test2() {
-    root = TreeUtils.constructBinaryTree(Arrays.asList(1, 2, 2, null, 3, null, 3));
-    assertEquals(false, solution1.isSymmetric(root));
-  }
+    private static _101.Solution1 solution1;
+    private static _101.Solution2 solution2;
+    private static TreeNode root;
+
+    @BeforeClass
+    public static void setup() {
+        solution1 = new _101.Solution1();
+        solution2 = new _101.Solution2();
+    }
+
+    @Test
+    public void test1() {
+        root = TreeUtils.constructBinaryTree(Arrays.asList(1, 2, 2, 3, 4, 4, 3));
+        assertEquals(true, solution1.isSymmetric(root));
+        assertEquals(true, solution2.isSymmetric(root));
+    }
+
+    @Test
+    public void test2() {
+        root = TreeUtils.constructBinaryTree(Arrays.asList(1, 2, 2, null, 3, null, 3));
+        assertEquals(false, solution1.isSymmetric(root));
+        assertEquals(false, solution2.isSymmetric(root));
+    }
 }
