Basic TRIE

Create a basic TRIE from the words.

Author: joydeep1982

BasicTRIE

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+package org.ds_algo;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Map.Entry;
+import java.util.Set;
+
+public class BasicTRIE {
+
+	public static void main(String[] args) {
+		Node head = new Node();
+		head.ch = null;
+
+		addString("hacker", head);
+		addString("hack", head);
+		addString("hacking", head);
+		addString("hacked", head);
+		
+		addString("animal", head);
+		addString("anagram", head);
+		addString("angry", head);
+		addString("antelope", head);
+		addString("anagrams", head);
+
+		System.out.println(findInTRIE("hack", head));
+	}
+
+	private static int findInTRIE(String str, Node head) {
+		Node n = head;
+		for (int i = 0; i < str.length(); i++) {
+			if (n.children.get(str.charAt(i)) == null) {
+				return 0;
+			}
+			n = n.children.get(str.charAt(i));
+		}
+		return n.count;
+	}
+
+	private static void printTRIE(Node head, int level) {
+		for (int i = 0; i < level; i++) {
+			System.out.print(" ");
+		}
+		System.out.println(head.ch);
+		Set<Entry<Character, Node>> entries = head.children.entrySet();
+		for (Entry<Character, Node> entry : entries) {
+			printTRIE(entry.getValue(), level + 1);
+		}
+	}
+
+	public static void addString(String str, Node head) {
+		Node n = head;
+		for (int i = 0; i < str.length(); i++) {
+			n = add(str.charAt(i), n);
+		}
+	}
+
+	public static Node add(char ch, Node head) {
+		Node n = head.children.get(ch);
+		if (n == null) {
+			n = new Node();
+			n.ch = ch;
+			head.children.put(ch, n);
+		}
+		n.count++;
+		return n;
+	}
+}
+
+class Node {
+	Character ch;
+	Integer count = 0;
+	Map<Character, Node> children = new HashMap<>();
+}