io.github.deepeshpatel.jnumbertools.numbersystem.Factoradic Maven / Gradle / Ivy
/*
* JNumberTools Library v1.0.3
* Copyright (c) 2022 Deepesh Patel ([email protected])
*/
package io.github.deepeshpatel.jnumbertools.numbersystem;
import java.io.Serializable;
import java.math.BigInteger;
import java.util.Collections;
import java.util.List;
import java.util.stream.IntStream;
/**
* Encapsulates the Factoradic representation of a positive integer value.
*
* Factoradic is a numeral system where the weight of each digit is the factorial of its position index.
* This class provides methods to create a Factoradic representation from an integer,
* and to obtain the decimal equivalent of a Factoradic representation.
*
* @author Deepesh Patel
*/
public final class Factoradic implements Serializable {
/**
* The Factoradic representation of the integer, where each value represents a digit in the Factoradic numeral system.
* The list is ordered from the least significant digit to the most significant.
*/
public transient final List factoradicValues;
/**
* The decimal equivalent of this Factoradic representation.
*/
public final BigInteger decimalValue;
private Factoradic(List factoradicValues, BigInteger decimalValue) {
this.factoradicValues = Collections.unmodifiableList(factoradicValues);
this.decimalValue = decimalValue;
}
/**
* Creates a {@link Factoradic} instance from a positive integer.
*
* @param positiveInt the positive integer to be converted to Factoradic representation.
* @return a {@link Factoradic} instance representing the given positive integer.
*/
public static Factoradic of(BigInteger positiveInt) {
int[] intValues = FactoradicAlgorithms.intToFactoradic(positiveInt);
var values = IntStream.of(intValues).boxed().toList();
return new Factoradic(values, positiveInt);
}
/**
* Creates a {@link Factoradic} instance from a positive long value.
*
* @param positiveInt the positive long value to be converted to Factoradic representation.
* @return a {@link Factoradic} instance representing the given positive long value.
*/
public static Factoradic of(long positiveInt) {
return Factoradic.of(BigInteger.valueOf(positiveInt));
}
@Override
public String toString() {
// Print in reverse for readability.
StringBuilder sb = new StringBuilder("[");
for (int i = factoradicValues.size() - 1; i > 0; i--) {
sb.append(factoradicValues.get(i));
sb.append(", ");
}
sb.append(factoradicValues.get(0));
sb.append("]");
return sb.toString();
}
@Override
public boolean equals(Object o) {
if (this == o) return true;
if (o == null || getClass() != o.getClass()) return false;
Factoradic that = (Factoradic) o;
return decimalValue.equals(that.decimalValue);
}
@Override
public int hashCode() {
return decimalValue.hashCode();
}
}