Create TriesAlgorithm.java

TriesAlgorithm.java

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+//Tries implementation in java
+public class TrieNode {
+	char data;
+	boolean isTerminal;
+	TrieNode childrenArr[]; //initialize an array of reference of the children
+	int childCount;
+
+	public TrieNode(char data) {
+		this.data = data;
+		this.isTerminal = false;
+		this.childrenArr = new TrieNode[26]; // create an array size of 26 where the reference of the child will be stored
+		this.childCount = 0;
+	}
+}
+
+
+public class TriesImplementation {
+	//tries implementation through root
+	private TrieNode root;
+
+	public TriesImplementation() {
+		root = new TrieNode('\0');
+	}
+
+	//insert
+
+	private void insertHelper(TrieNode root, String word) {
+		if(word.length() == 0) {
+			root.isTerminal = true;
+			return;
+		}
+		int childIndex = word.charAt(0) - 'A'; //here we just subtract the ascii value of 0th index character and ascii value of capital A(65) so that we get the index at array
+		TrieNode child = root.childrenArr[childIndex];
+		//if the character is not present in the array previously
+		if(child == null) {
+			child = new TrieNode(word.charAt(0));// creating node for 0th index element
+			//after creating node add the element into the array at particular index
+			root.childrenArr[childIndex] = child;
+		}
+		insertHelper(child, word.substring(1)); 
+		//suppose you want to insert "NOTE" word then after creating node for N then remaining substring is "OTE" this is the meaning for substring(1) after that "TE" then "E"
+		root.childCount++;
+	}
+
+	public void insert(String word) {
+		insertHelper(root, word);
+	}
+
+	//Search
+
+	private boolean searchHelper(TrieNode root, String word) {
+
+		if(word.length() == 0) {
+			return root.isTerminal;
+		}
+		int childIndex = word.charAt(0) - 'A';
+		TrieNode child = root.childrenArr[childIndex];
+		if(child == null) {
+			return false;
+		}
+		return searchHelper(child, word.substring(1));
+	}
+
+	public boolean search(String word) {
+		return searchHelper(root,word);
+	}
+
+	//Delete
+
+	private void removeHelper(TrieNode root, String word) {
+		if(word.length() == 0) {
+			root.isTerminal = false;
+			return;
+		}
+		int childIndex = word.charAt(0) - 'A';
+		TrieNode child = root.childrenArr[childIndex];
+		if(child == null) {
+			return;
+		}
+		removeHelper(child, word.substring(1));
+		if(! child.isTerminal && child.childCount==0) {
+			root.childrenArr[childIndex] = null;
+			root.childCount--;
+		}
+	}
+
+	public void remove(String word) {
+		removeHelper(root,word);
+	}
+}
+
+public class TrieUse {
+
+	public static void main(String[] args) {
+
+		TriesImplementation t = new TriesImplementation();
+		t.insert("NOTE");
+		t.insert("AND");
+		t.insert("AN");
+
+		System.out.println(t.search("AND"));
+		t.remove("AND");
+		System.out.println(t.search("AND"));
+
+	}
+
+}