2022-05-19 update: added "Flip Equivalent Binary Trees"

Author: fartem

src/main/java/com/smlnskgmail/jaman/leetcodejava/medium/FlipEquivalentBinaryTrees.java

@@ -0,0 +1,32 @@
+package com.smlnskgmail.jaman.leetcodejava.medium;
+
+import com.smlnskgmail.jaman.leetcodejava.support.TreeNode;
+
+// https://leetcode.com/problems/flip-equivalent-binary-trees
+public class FlipEquivalentBinaryTrees {
+
+    private final TreeNode root1;
+    private final TreeNode root2;
+
+    public FlipEquivalentBinaryTrees(TreeNode root1, TreeNode root2) {
+        this.root1 = root1;
+        this.root2 = root2;
+    }
+
+    public boolean solution() {
+        return countFlipEquivalents(root1, root2);
+    }
+
+    private boolean countFlipEquivalents(TreeNode root1, TreeNode root2) {
+        if (root1 == root2) {
+            return true;
+        }
+        if (root1 == null || root2 == null || root1.val != root2.val) {
+            return false;
+        }
+        boolean original = countFlipEquivalents(root1.right, root2.right) && countFlipEquivalents(root1.left, root2.left);
+        boolean switched = countFlipEquivalents(root1.right, root2.left) && countFlipEquivalents(root1.left, root2.right);
+        return original || switched;
+    }
+
+}

src/test/java/com/smlnskgmail/jaman/leetcodejava/medium/FlipEquivalentBinaryTreesTest.java

@@ -0,0 +1,52 @@
+package com.smlnskgmail.jaman.leetcodejava.medium;
+
+import com.smlnskgmail.jaman.leetcodejava.support.TreeNode;
+import org.junit.Test;
+
+import static org.junit.Assert.assertTrue;
+
+public class FlipEquivalentBinaryTreesTest {
+
+    @Test
+    public void defaultTest() {
+        assertTrue(
+                new FlipEquivalentBinaryTrees(
+                        new TreeNode(
+                                1,
+                                new TreeNode(
+                                        2,
+                                        new TreeNode(4),
+                                        new TreeNode(
+                                                5,
+                                                new TreeNode(7),
+                                                new TreeNode(8)
+                                        )
+                                ),
+                                new TreeNode(
+                                        3,
+                                        new TreeNode(6),
+                                        null
+                                )
+                        ),
+                        new TreeNode(
+                                1,
+                                new TreeNode(
+                                        3,
+                                        null,
+                                        new TreeNode(6)
+                                ),
+                                new TreeNode(
+                                        2,
+                                        new TreeNode(4),
+                                        new TreeNode(
+                                                5,
+                                                new TreeNode(8),
+                                                new TreeNode(7)
+                                        )
+                                )
+                        )
+                ).solution()
+        );
+    }
+
+}