Radix tree

binary_tree/src/RadixTree.java

@@ -0,0 +1,148 @@
+package datastructures;
+
+import java.util.Locale;
+
+import datastructures.LinkedList;
+
+class RadixNode {
+	private String data;
+	private LinkedList<RadixNode> children;
+	private Locale locale;
+
+	public RadixNode(String data, Locale locale) {
+		if (locale == null)
+			locale = Locale.getDefault();
+		this.locale = locale;
+		this.data = data.toLowerCase(locale);
+		this.children = new LinkedList<>();
+	}
+
+	public RadixNode(String data) {
+		this(data,Locale.getDefault());
+	}
+
+	public int size() {
+		return data.length();
+	}
+
+	public int indexDiffer(RadixNode cmp) {
+		int min = Math.min(cmp.data.length(), data.length());
+		for (int i = 0 ; i < min; i++)
+			if (cmp.data.charAt(i) != data.charAt(i))
+				return i;
+		return min;
+	}
+
+	private void addEmpty(RadixNode node) {
+		if (node.data.isEmpty() && !children.isEmpty()) {
+			for (RadixNode n : children)
+				if (n.data.isEmpty()) return;
+			children.append(new RadixNode("",locale));
+		}
+	}
+
+	private void addNode(RadixNode node, int i) {
+		if (i < data.length()) {
+			RadixNode n = new RadixNode(data.substring(i),locale);
+			n.children = children;
+			setData(data.substring(0, i));
+			children = new LinkedList<>();
+			children.append(n);
+		} else
+			addEmpty(node);
+	}
+
+	private void appendChild(RadixNode node) {
+		if (node.data.isEmpty())
+			return;
+		if (children.isEmpty() && !data.isEmpty())
+			children.append(new RadixNode("",locale));
+		else
+			for (RadixNode n : children) {
+				int i = n.indexDiffer(node);
+				if (i > 0) {
+					n.insert(node);
+					return;
+				}
+			}
+		children.append(node);
+	}
+
+	public void insert(RadixNode node) {
+		// consume this node.
+		int i = indexDiffer(node);
+		node.setData(node.data.substring(i));
+		// test if node need to be splited...
+		if (i > 0 && i <= data.length()) {
+			// split node
+			addNode(node, i);
+		}
+		// append remaining data
+		appendChild(node);
+	}
+
+	private void setData(String data) {
+		this.data = data.toLowerCase(locale);
+	}
+
+	public String getData() {
+		return data;
+	}
+
+	void print(int l) {
+		if (l > 0) {
+			System.out.print(new String(new char[l-1]).replace("\0","  "));
+			System.out.println("["+data+"]");
+		}
+		for (RadixNode n : children)
+			n.print(l+1);
+	}
+
+	public boolean contains(RadixNode needle) {
+		// consume this node.
+		int i = indexDiffer(needle);
+		needle.setData(needle.data.substring(i));
+		if (needle.data.isEmpty())
+			return needleConsumed();
+		for (RadixNode n : children) {
+			i = n.indexDiffer(needle);
+			if (i > 0)
+				return n.contains(needle);
+		}
+		return false;
+	}
+
+	private boolean needleConsumed() {
+		if (children.isEmpty())
+			return true;
+		for (RadixNode n : children)
+			if (n.data.isEmpty())
+				return true;
+		return false;
+	}
+}
+
+public class RadixTree {
+	private Locale locale;
+	private RadixNode root;
+
+	public RadixTree() {
+		root = new RadixNode("");
+	}
+
+	public void setLocale(Locale locale) {
+		this.locale = locale;
+	}
+
+	public void insert(String needle) {
+		root.insert(new RadixNode(needle,locale));
+	}
+
+	public void print() {
+		root.print(0);
+	}
+
+	public boolean contains(String needle) {
+		return root.contains(new RadixNode(needle));
+	}
+}