208 | Implement Trie (Prefix Tree) | Java

Java/Trie.java

@@ -0,0 +1,78 @@
+import java.util.Scanner;
+import java.util.Stack;
+
+class Node{
+  boolean word_end;
+  Node[] children = new Node[26];
+
+  Node(){
+    word_end = false;
+    for(int i = 0;i < 26;i++){
+      children[i] = null;
+    }
+  }
+}
+
+class Trie{
+  private static Node root;
+
+  static void insert(String str){
+    Node current = root;
+    for(int i = 0;i < str.length();i++){
+      char ch = str.charAt(i);
+      if(current.children[ch-'a'] == null){
+        current.children[ch-'a'] = new Node();
+      }
+      current = current.children[ch-'a'];
+    }
+    current.word_end = true;
+    System.out.println("String inserted");
+  }
+
+  static void search(String str){
+    Node current = root;
+    for(int i = 0;i < str.length();i++){
+      char ch = str.charAt(i);
+      if(current.children[ch-'a'] == null){
+        System.out.println("Word does not exist");
+        return;
+      }
+      else{
+        current = current.children[ch-'a'];
+      }
+    }
+    if(current.word_end){
+      System.out.println("Word found");
+    }
+    else{
+      System.out.println("Word does not exist");
+    }
+  }
+
+
+  public static void main(String[] args) {
+    Scanner sc = new Scanner(System.in);
+    int choice = 0;
+    root = new Node();
+
+    while(choice != 3){
+      System.out.println("Select one operation : 1) Insert\t2) Search\t3) Exit");
+      choice = sc.nextInt();
+      switch(choice){
+        case 1:
+          System.out.print("Enter a string to insert - ");
+          String str = sc.next();
+          insert(str);
+          break;
+        case 2:
+          System.out.print("Enter a string to search -");
+          String st = sc.next();
+          search(st);
+          break;
+        default:
+          break;
+        }
+    }
+
+  }
+}