How to induce upwardly one's heed if a string has all unique characters inward Java?

This is i of the mutual string based coding job from programming chore interviews. You demand to write a programme to create upwardly one's heed if a given string has all unique characters or not. For representative input= "Java" together with thus your role should render faux because all characters are non unique, together with if the input is "Python" together with thus your programme should render truthful because all characters inward Python are unique. For the role of this problem, yous tin assume the given String entirely contains ASCII printable characters, though yous should e'er verify that alongside the interviewer. You tin too assume that your solution needs to case-sensitive i.e. "P" together with "p" volition move considered 2 unlike characters together with a string containing a missive of the alphabet inward both upper-case missive of the alphabet together with the small-scale representative volition move considered unique. You are too gratuitous to solve the job inward house of using whatever additional information structure.

The outset solution which comes to heed to solve this job is yesteryear using a Set information structure. Influenza A virus subtype H5N1 Set is an unordered collection which doesn't allow duplicates. The JDK provides several Set implementations e.g. HashSet, TreeSet or LinkedHashSet only to solve this job nosotros tin work full general role HashSet. The add() method is used to insert an chemical factor into Set together with this method returns truthful if an chemical factor is successfully inserted otherwise it returns faux i.e. when an chemical factor is already introduce inward the Set.

If nosotros larn through each grapheme of String together with insert them into Set using add() method together with thus nosotros tin discovery if all characters of String are unique or not. If at that topographic point are whatever duplicate characters together with thus add() volition render faux together with nosotros tin halt our programme returning that all characters of String are non unique.

Here is the exact algorithm to solve this problem:

1) Create a Set e.g. HashSet
2) Get all characters of String using chars()
3) loop over all characters together with insert into Set i at a time
4) If add() method render faux together with thus terminate the programme because non all characters are unique.
5) If all characters are successfully inserted together with thus render truthful because all characters of String is unique

Program to create upwardly one's heed if a string has all unique characters inward Java

Here is a Java programme to convert higher upwardly algorithm into code:

import java.util.HashSet; import java.util.Scanner; import java.util.Set;  /*  * Java Program to depository fiscal establishment gibe if all characters of String are unique.   */ public class Demo {    public static void main(String[] args) throws Exception {      // create Scanner to read user input     Scanner sc = new Scanner(System.in);      System.out.println("Please larn inward a String");     String input = sc.nextLine();      if (isUnique(input)) {       System.out.println("All characters of String are unique");     } else {       System.out.println("All characters of String are non unique");     }      sc.close();   }    /**    * Returns truthful if all characters of given String are unique    *     * @param input    * @return truthful if no duplicate characters    */   public static boolean isUnique(String input) {     // Create a Set to insert characters     Set<Character> set = new HashSet<>();      // larn all characters shape String     char[] characters = input.toCharArray();      for (Character c : characters) {       if (!set.add(c)) {         return false;       }     }     return true;   } } Output Please enter a String Java All characters of String are not unique Please enter a String Python All characters of String are unique

From the output, it's clear that our programme is working fine. When the user enters "Java" it returns that all characters are non unique because "a" is repeated inward "Java", only when the user enters "Python" it prints "all characters are unique" because at that topographic point is no duplicate grapheme inward "Python".

That's all well-nigh how to depository fiscal establishment gibe if given string has all unique characters. As I said, at that topographic point are multiple ways to create it e.g. yous tin create it inward place, or yous tin work additional information construction e.g. laid or hash tabular array to create upwardly one's heed if a string has all unique characters. This job is too asked every bit for how to depository fiscal establishment gibe if String contains duplicates or finding the repeated characters from the string. You tin work the same technique to solve those problems every bit well.

Further Reading
The Cracking the Coding Interview
The Programming Interview Exposed

Thanks for reading this article thus far. If yous similar this interview enquiry together with my explanation together with thus delight portion alongside your friends together with colleagues. If yous convey whatever doubtfulness together with thus delight drib a comment.