二叉树的序列化和反序列化

src/test/java/com/ossez/lang/tutorial/tests/lintcode/LintCode0007SerializeAndDeserialize.java

@@ -0,0 +1,131 @@
+package com.ossez.lang.tutorial.tests.lintcode;
+
+import java.util.ArrayList;
+
+import org.junit.Test;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import com.ossez.lang.tutorial.models.TreeNode;
+
+/**
+ * <p>
+ * 7
+ * <ul>
+ * <li>@see <a href=
+ * "https://www.cwiki.us/display/ITCLASSIFICATION/Serialize+and+Deserialize+Binary+Tree">https://www.cwiki.us/display/ITCLASSIFICATION/Serialize+and+Deserialize+Binary+Tree</a>
+ * <li>@see<a href=
+ * "https://www.lintcode.com/problem/serialize-and-deserialize-binary-tree">https://www.lintcode.com/problem/serialize-and-deserialize-binary-tree</a>
+ * </ul>
+ * </p>
+ * 
+ * @author YuCheng
+ *
+ */
+public class LintCode0007SerializeAndDeserialize {
+
+	private final static Logger logger = LoggerFactory.getLogger(LintCode0007SerializeAndDeserialize.class);
+
+	/**
+	 * 
+	 */
+	@Test
+	public void testMain() {
+		logger.debug("BEGIN");
+		String data = "{3,9,20,#,#,15,7}";
+
+		System.out.println(serialize(deserialize(data)));
+
+	}
+
+	/**
+	 * Deserialize from array to tree
+	 * 
+	 * @param data
+	 * @return
+	 */
+	private TreeNode deserialize(String data) {
+		// NULL CHECK
+		if (data.equals("{}")) {
+			return null;
+		}
+
+		ArrayList<TreeNode> treeList = new ArrayList<TreeNode>();
+
+		data = data.replace("{", "");
+		data = data.replace("}", "");
+		String[] vals = data.split(",");
+
+		// INSERT ROOT
+		TreeNode root = new TreeNode(Integer.parseInt(vals[0]));
+		treeList.add(root);
+
+		int index = 0;
+		boolean isLeftChild = true;
+		for (int i = 1; i < vals.length; i++) {
+			if (!vals[i].equals("#")) {
+				TreeNode node = new TreeNode(Integer.parseInt(vals[i]));
+				if (isLeftChild) {
+					treeList.get(index).left = node;
+				} else {
+					treeList.get(index).right = node;
+				}
+				treeList.add(node);
+			}
+
+			// LEVEL
+			if (!isLeftChild) {
+				index++;
+			}
+
+			// MOVE TO RIGHT OR NEXT LEVEL
+			isLeftChild = !isLeftChild;
+		}
+
+		return root;
+
+	}
+
+	/**
+	 * 
+	 * @param root
+	 * @return
+	 */
+	public String serialize(TreeNode root) {
+		// write your code here
+		if (root == null) {
+			return "{}";
+		}
+
+		ArrayList<TreeNode> queue = new ArrayList<TreeNode>();
+		queue.add(root);
+
+		for (int i = 0; i < queue.size(); i++) {
+			TreeNode node = queue.get(i);
+			if (node == null) {
+				continue;
+			}
+			queue.add(node.left);
+			queue.add(node.right);
+		}
+
+		while (queue.get(queue.size() - 1) == null) {
+			queue.remove(queue.size() - 1);
+		}
+
+		StringBuilder sb = new StringBuilder();
+		sb.append("{");
+		sb.append(queue.get(0).val);
+		for (int i = 1; i < queue.size(); i++) {
+			if (queue.get(i) == null) {
+				sb.append(",#");
+			} else {
+				sb.append(",");
+				sb.append(queue.get(i).val);
+			}
+		}
+		sb.append("}");
+		return sb.toString();
+	}
+
+}