# Hackerrank Java BitSet Solution

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 of  is called a set bit.

Given  BitSets,  and , of 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.

Input Format

The first line contains  space-separated integers,  (the length of both BitSets  and ) and  (the number of operations to perform), respectively.
The  subsequent lines each contain an operation in one of the following forms:

In the list above,  is the integer  or , where  denotes  and  denotes .
is an integer denoting a bit's index in the BitSet corresponding to .

For the binary operations , , and , operands are read from left to right and the BitSet resulting from the operation replaces the contents of the first operand. For example:

AND 2 1


is the left operand, and  is the right operand. This operation should assign the result of  to .

Constraints

Output Format

After each operation, print the respective number of set bits in BitSet  and BitSet  as  space-separated integers on a new line.

Sample Input

5 4
AND 1 2
SET 1 4
FLIP 2 2
OR 2 1


Sample Output

0 0
1 0
1 1
1 2


Explanation

Initially: , , , and . At each step, we print the respective number of set bits in  and  as a pair of space-separated integers on a new line.

,
The number of set bits in  and  is .

Set  to  ().
, .
The number of set bits in  is  and  is .

Flip  from  () to  ().
, .
The number of set bits in  is  and  is .

.
, .
The number of set bits in  is  and  is .

### Solution in java8

Approach 1.

import java.io.*;
import java.util.*;

public class Solution {
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 ( 0 < m-- ) {
String op = get.next();
int x = get.nextInt();
int y = get.nextInt();

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

System.out.printf("%d %d%n", b1.cardinality(), b2.cardinality());
}
}
}

Approach 2.

import java.io.*;
import java.util.*;

public class Solution {

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 ( 0 < m-- ) {
String op = get.next();
int x = get.nextInt();
int y = get.nextInt();

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

System.out.printf("%d %d%n", b1.cardinality(), b2.cardinality());
}
}
}

Approach 3.

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

public class Solution {

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 ( 0 < m-- ) {
String op = get.next();
int x = get.nextInt();
int y = get.nextInt();

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

System.out.printf("%d %d%n", b1.cardinality(), b2.cardinality());
}
}
}