Tree isomorphism

Author: williamfiset

com/williamfiset/algorithms/graphtheory/treealgorithms/TreeIsomorphism.java

@@ -127,7 +127,7 @@ private static boolean areIsomorphic(TreeNode root1, TreeNode root2) {
   }
 
   // Constructs the canonical form representation of a tree as a string.
-  private static String encode(TreeNode node) {
+  public static String encode(TreeNode node) {
     if (node == null) {
       return "()";
     }

com/williamfiset/algorithms/graphtheory/treealgorithms/TreeIsomorphismWithBfs.java

@@ -139,7 +139,7 @@ public static String encodeTree(List<List<Integer>> tree) {
 
     // Two nodes remain and we need to combine their labels
     String l2 = map[leafs.get(1)];
-    return (l1.compareTo(l2) < 0) ? (l1 + l2) : (l2 + l1);
+    return ((l1.compareTo(l2) < 0) ? (l1 + l2) : (l2 + l1));
   }
 
   public static boolean treesAreIsomorphic(List<List<Integer>> tree1, List<List<Integer>> tree2) {

javatests/com/williamfiset/algorithms/graphtheory/treealgorithms/TreeIsomorphismWithBfsTest.java

@@ -1,10 +1,16 @@
+// To run this test in isolation from root folder:
+//
+// $ gradle test --tests
+// javatests.com.williamfiset.algorithms.graphtheory.treealgorithms.TreeIsomorphismWithBfsTest
+
 package javatests.com.williamfiset.algorithms.graphtheory.treealgorithms;
 
 import static com.google.common.truth.Truth.assertThat;
 import static com.williamfiset.algorithms.graphtheory.treealgorithms.TreeIsomorphismWithBfs.addUndirectedEdge;
 import static com.williamfiset.algorithms.graphtheory.treealgorithms.TreeIsomorphismWithBfs.createEmptyTree;
 import static com.williamfiset.algorithms.graphtheory.treealgorithms.TreeIsomorphismWithBfs.encodeTree;
 import static com.williamfiset.algorithms.graphtheory.treealgorithms.TreeIsomorphismWithBfs.treesAreIsomorphic;
+import static com.williamfiset.algorithms.graphtheory.treealgorithms.TreeIsomorphism.TreeNode;
 
 import java.util.*;
 import org.junit.*;
@@ -119,4 +125,59 @@ public void testSlidesExample() {
     String expectedEncoding = "(((()())(()())())((())()()())(()()()))";
     assertThat(treeEncoding).isEqualTo(expectedEncoding);
   }
+
+  @Test
+  public void t() {
+    List<List<Integer>> tree = createEmptyTree(10);
+
+    TreeNode node0 = new TreeNode(0);
+    TreeNode node1 = new TreeNode(1);
+    TreeNode node2 = new TreeNode(2);
+    TreeNode node3 = new TreeNode(3);
+    TreeNode node4 = new TreeNode(4);
+    TreeNode node5 = new TreeNode(5);
+    TreeNode node6 = new TreeNode(6);
+    TreeNode node7 = new TreeNode(7);
+    TreeNode node8 = new TreeNode(8);
+    TreeNode node9 = new TreeNode(9);
+
+    node0.addChildren(node1, node2, node3);
+    node1.addChildren(node4, node5);
+    node5.addChildren(node9);
+    node2.addChildren(node6, node7);
+    node3.addChildren(node8);
+
+    System.out.println(com.williamfiset.algorithms.graphtheory.treealgorithms.TreeIsomorphism.encode(node0));
+    
+    // (((())())(()())(()))
+    //  ((())())               
+    //          (()())
+    //                (())
+    //             
+
+    // (()())
+    // (())
+    // (())
+
+    // ((()())(()))
+    // ((())())
+    // 
+    // ((()())(()))((())())
+
+
+    // (((()())(()))((())()))
+    //   (()())
+    //         (())
+    //      
+    //             ((())())
+    //
+  }
 }
+
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