added solution and test cases for 449 (fishercoder1534#143)

ashmichheda · web-flow · commit e71917913b81 · 2021-01-08T18:38:25.000-08:00
diff --git a/src/main/java/com/fishercoder/solutions/_449.java b/src/main/java/com/fishercoder/solutions/_449.java
@@ -2,6 +2,7 @@
 
 import com.fishercoder.common.classes.TreeNode;
 
+import java.util.Arrays;
 import java.util.LinkedList;
 import java.util.Queue;
 
@@ -150,4 +151,43 @@ public TreeNode deserialize(String data) {
             return root;
         }
     }
+    public static class Solution4 {
+        private static final String NULL_SYMBOL = "X";
+        private static final String DELIMITER = ",";
+
+        // Encodes a tree to a single string.
+        public String serialize(TreeNode root) {
+
+            // If we have a null symbol, encode it to NULL_SYMBOL
+            if(root == null)
+                return NULL_SYMBOL + DELIMITER;
+
+            String leftSubtree = serialize(root.left);
+            String rightSubtree = serialize(root.right);
+
+            return root.val + DELIMITER + leftSubtree + rightSubtree;
+        }
+
+        // Decodes your encoded data to tree.
+        public TreeNode deserialize(String data) {
+
+            Queue<String> nodesLeftToSerialize = new LinkedList<>();
+            nodesLeftToSerialize.addAll(Arrays.asList(data.split(DELIMITER)));
+            return deserializeHelper(nodesLeftToSerialize);
+
+        }
+        private TreeNode deserializeHelper(Queue<String> nodesLeft){
+
+            // remove the node
+            String nodeLeftToSerialize = nodesLeft.poll();
+            // base case
+            if(nodeLeftToSerialize.equals(NULL_SYMBOL)){
+                return null;
+            }
+            TreeNode newNode = new TreeNode(Integer.valueOf(nodeLeftToSerialize));
+            newNode.left = deserializeHelper(nodesLeft);
+            newNode.right = deserializeHelper(nodesLeft);
+            return newNode;
+        }
+    }
 }
diff --git a/src/test/java/com/fishercoder/_449Test.java b/src/test/java/com/fishercoder/_449Test.java
@@ -12,13 +12,15 @@ public class _449Test {
     private static _449.Solution1 solution1;
     private static _449.Solution2 solution2;
     private static _449.Solution3 solution3;
+    private static _449.Solution4 solution4;
     private static TreeNode expectedRoot;
 
     @BeforeClass
     public static void setup() {
         solution1 = new _449.Solution1();
         solution2 = new _449.Solution2();
         solution3 = new _449.Solution3();
+        solution4 = new _449.Solution4();
     }
 
     @Before
@@ -34,6 +36,7 @@ public void test1() {
         assertEquals(expectedRoot.toString(), solution1.deserialize(solution1.serialize(expectedRoot)).toString());
         assertEquals(expectedRoot.toString(), solution2.deserialize(solution2.serialize(expectedRoot)).toString());
         assertEquals(expectedRoot.toString(), solution3.deserialize(solution3.serialize(expectedRoot)).toString());
+        assertEquals(expectedRoot.toString(), solution4.deserialize(solution4.serialize(expectedRoot)).toString());
     }
 
     @Test
@@ -44,5 +47,6 @@ public void test2() {
         assertEquals(expectedRoot.toString(), solution1.deserialize(solution1.serialize(expectedRoot)).toString());
         assertEquals(expectedRoot.toString(), solution2.deserialize(solution2.serialize(expectedRoot)).toString());
         assertEquals(expectedRoot.toString(), solution3.deserialize(solution3.serialize(expectedRoot)).toString());
+        assertEquals(expectedRoot.toString(), solution4.deserialize(solution4.serialize(expectedRoot)).toString());
     }
 }
