Create TreeNode.java

Author: PengFTang

__Supports/TreeNode.java

@@ -0,0 +1,79 @@
+// package supports;
+
+import java.util.LinkedList;
+import java.util.Queue;
+
+public class TreeNode {
+    public int val;
+    public TreeNode left;
+    public TreeNode right;
+    public TreeNode(int x) { val = x; }
+    
+    public static TreeNode constructTreeFromString(String str) {
+    	String[] strs = str.split(",");
+		int L = strs.length;
+		if(L < 1) return null;
+		
+		TreeNode root = new TreeNode(Integer.parseInt(strs[0]));
+		
+		Queue<TreeNode> q = new LinkedList<>();
+		q.add(root);
+		int i = 0;
+		while(i<L-1) {
+			TreeNode current = q.peek();
+			q.poll();
+			if(i<L-1 && !strs[++i].equals("#")) {
+				current.left = new TreeNode(Integer.parseInt(strs[i]));
+				current.left.left = null;
+				current.left.right = null;
+				q.add(current.left);
+			}
+			if(i<L-1 && !strs[++i].equals("#")) {
+				current.right = new TreeNode(Integer.parseInt(strs[i]));
+				current.right.left = null;
+				current.right.right = null;
+				q.add(current.right);
+			}
+		}
+		return root;
+	}	
+    
+	public static void preorderTraversal(TreeNode root) {
+		//TreeNode root = this;
+		//if(root == null) return;
+		System.out.print(root.val + "\t");
+		if(root.left!=null)
+			preorderTraversal(root.left);
+		if(root.right!=null)
+			preorderTraversal(root.right);
+	}
+	public static void inorderTraversal(TreeNode root) {
+		//TreeNode root = this;
+		if(root == null) return;
+		if(root.left!=null)
+			inorderTraversal(root.left);
+		System.out.print(root.val + "\t");
+		if(root.right!=null)
+			inorderTraversal(root.right);
+	}
+	public static void postorderTraversal(TreeNode root) {
+		//TreeNode root = this;
+		if(root == null) return;
+		if(root.left!=null)
+			postorderTraversal(root.left);
+		if(root.right!=null)
+			postorderTraversal(root.right);
+		System.out.print(root.val + "\t");
+	}
+	
+	public static String toString(TreeNode root) {
+	    return toString(root, new StringBuffer(), true, new StringBuffer()).toString();
+	}
+	public static StringBuffer toString(TreeNode root, StringBuffer prefix, boolean isTail, StringBuffer sb) {
+	    if(root.right!=null) toString(root.right, new StringBuffer().append(prefix).append(isTail ? "©¦   " : "    "), false, sb);
+	    String str = " " + root.val + " ";
+	    sb.append(prefix).append(isTail ? "©¸©¤©¤" : "©°©¤©¤").append(str).append("\n");
+	    if(root.left!=null) toString(root.left, new StringBuffer().append(prefix).append(isTail ? "    " : "©¦   "), true, sb);
+	    return sb;
+	}
+}