Problem
Remove the duplicate characters from the given string.
Solution
- Use Java Set. LinkedHashSet used as it preserves insertion order. Complexity for adding items in LinkedhashSet is O(1).
- This solution prints the duplicates while traversing through the array.
- Time complexity – O(n) Linear.
- Implementation in Java.
package com.computepatterns.problemsolving.string;
import java.util.LinkedHashSet;
import java.util.Set;
/**
* Remove duplicates from the given String.
* Leverage JDK set. Set doesn't allow duplicates.
*/
public class RemoveDuplicates {
String removeDuplicates(String input){
// LinkedHashSet over HashSet as LinkedHashSet preserve order.
// Set doesn't allow duplicates.
Set<Character> characterSet = new LinkedHashSet<Character>();
for (int i = 0; i < input.length(); i++) {
if(!characterSet.add(input.charAt(i))){
System.out.printf("Duplicate character - %c\n", input.charAt(i));
};
}
return characterSet.toString();
}
public static void main(String[] args) {
String output = new RemoveDuplicates().removeDuplicates("Hello World!!!");
System.out.printf("String after removing duplicates - %s", output);
}
}