Java BitSet HackerRank Solution

Problem Statement

Java’s BitSet class implements a vector of bit values (i.e.:  () or  ()) that grows as needed, allowing us to easily manipulate bits while optimizing space (when compared to other collections). Any element having a bit value is called a set bit.

Given  BitSets,  and, of a size where all bits in both BitSets are initialized to, perform a series of operations. After each operation, print the number of set bits in the respective BitSets as two space-separated integers on a new line.

Solution

package hackerrank.corejava.dataStructures;

import java.util.BitSet;
import java.util.Scanner;

public class BitSetExample {
  public static void main(String[] args) {
    Scanner get = new Scanner(System.in);
    int N = get.nextInt();
    int M = get.nextInt();

    BitSet B1 = new BitSet(N);
    BitSet B2 = new BitSet(N);
    BitSet[] bitset = new BitSet[3];

    bitset[1] = B1;
    bitset[2] = B2;

    while ( M-- > 0 ) {
      String op = get.next();
      int x = get.nextInt();
      int y = get.nextInt();

      switch (op) {
        case "AND" -> bitset[x].and(bitset[y]);
        case "OR" -> bitset[x].or(bitset[y]);
        case "XOR" -> bitset[x].xor(bitset[y]);
        case "FLIP" -> bitset[x].flip(y);
        case "SET" -> bitset[x].set(y);
      }

      System.out.printf("%d %d%n", B1.cardinality(), B2.cardinality());
    }
  }
}