Add 297_Serialize_and_Deserialize_Binary_Tree.java

Author: Sean Prashad

Tree Depth First Search/297_Serialize_and_Deserialize_Binary_Tree.java

@@ -0,0 +1,66 @@
+public class Codec {
+
+ // Encodes a tree to a single string.
+ public String serialize(TreeNode root) {
+ if (root == null) {
+ return "";
+ }
+
+ StringBuilder sb = new StringBuilder();
+ Queue<TreeNode> q = new LinkedList<>();
+ q.offer(root);
+
+ while (!q.isEmpty()) {
+ int levelSize = q.size();
+
+ for (int i = 0; i < levelSize; i++) {
+ TreeNode t = q.poll();
+
+ if (t == null) {
+ sb.append("null ");
+ continue;
+ }
+
+ sb.append(t.val).append(" ");
+
+ q.offer(t.left);
+ q.offer(t.right);
+ }
+ }
+
+ return sb.toString();
+ }
+
+ // Decodes your encoded data to tree.
+ public TreeNode deserialize(String data) {
+ if (data == null || data.length() == 0) {
+ return null;
+ }
+
+ String[] nodes = data.split(" ");
+ Queue<TreeNode> q = new LinkedList<>();
+
+ TreeNode root = new TreeNode(Integer.parseInt(nodes[0]));
+ q.offer(root);
+
+ for (int i = 1; i < nodes.length; i++) {
+ TreeNode parent = q.poll();
+
+ if (!nodes[i].equals("null")) {
+ TreeNode left = new TreeNode(Integer.parseInt(nodes[i]));
+ parent.left = left;
+ q.offer(left);
+ }
+
+ ++i;
+
+ if (!nodes[i].equals("null")) {
+ TreeNode right = new TreeNode(Integer.parseInt(nodes[i]));
+ parent.right = right;
+ q.offer(right);
+ }
+ }
+
+ return root;
+ }
+}