# Base-2 in Java

## The problem#

On this problem you need to convert integers numbers from and to a negative-base binary system.

Destructive-base techniques can accommodate all the identical numbers as normal place-value techniques, however each constructive and damaging numbers are represented with out using a minus signal (or, in laptop illustration, an indication bit); this benefit is countered by an elevated complexity of arithmetic operations.

To assist perceive, the primary eight digits (in decimal) of the Base(-2) system is:

`[1, -2, 4, -8, 16, -32, 64, -128]`

Instance conversions:

`Decimal, negabinary`

``````6,   '11010'
-6,  '1110'
4,   '100'
18,  '10110'
-11, '110101'
``````

## The answer in Java code#

Choice 1:

``````public class Resolution {

public static String intToNegabinary(int i) {
return Integer.toBinaryString((i+0xAAAAAAAA)^0xAAAAAAAA);
}

public static int negabinaryToInt(String s) {
return s.chars().map(i->i-'0').scale back(0,(a,v)->v-2*a);
}

}
``````

Choice 2:

``````public class Resolution {

public static String intToNegabinary(int i) {
var sb = new StringBuilder();

whereas (i != 0) {
int the rest = Math.abs(i) % 2;
sb.append(the rest);
if (i < 0 && the rest > 0) i--;
i /= -2;
}
var outcome = sb.reverse().toString();
return outcome.isEmpty() ? "0" : outcome;
}

public static int negabinaryToInt(String s) {
var strReversed = new StringBuilder(s).reverse();
int outcome = 0;

for (int i = 0; i < strReversed.size(); i++)
if (strReversed.charAt(i) == '1')
outcome += Math.pow(-2, i);

return outcome;
}
}
``````

Choice 3:

``````public class Resolution {

public static String intToNegabinary(int i) {
return Integer.toUnsignedString(toNegabinary(i), 2);
}

public static int negabinaryToInt(String s) {
return fromNegabinary(Integer.parseUnsignedInt(s, 2));
}

public static int toNegabinary(int i) {
return (i + NEGATIVE_DIGITS) ^ NEGATIVE_DIGITS;
}

public static int fromNegabinary(int i) {
return (i ^ NEGATIVE_DIGITS) - NEGATIVE_DIGITS;
}

personal static remaining int NEGATIVE_DIGITS = 0xAAAAAAAA;

}
``````

## Check circumstances to validate our resolution#

``````import org.junit.Check;
import static org.junit.Assert.assertEquals;

public class SolutionTest {
@Check
public void testIntToNegabinary() {
assertEquals("11010", Resolution.intToNegabinary(6));
assertEquals("1110", Resolution.intToNegabinary(-6));
}

@Check
public void testNegabinaryToInt() {
assertEquals(6, Resolution.negabinaryToInt("11010"));
assertEquals(-6, Resolution.negabinaryToInt("1110"));
}

}
``````