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Add HigherLowerPowerOfTwo
algorithm (#5707)
This commit is contained in:
@ -30,6 +30,7 @@
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* [CountSetBits](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/CountSetBits.java)
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* [CountSetBits](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/CountSetBits.java)
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* [GrayCodeConversion](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/GrayCodeConversion.java)
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* [GrayCodeConversion](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/GrayCodeConversion.java)
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* [HammingDistance](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/HammingDistance.java)
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* [HammingDistance](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/HammingDistance.java)
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* [HigherLowerPowerOfTwo](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/HigherLowerPowerOfTwo.java)
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* [HighestSetBit](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/HighestSetBit.java)
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* [HighestSetBit](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/HighestSetBit.java)
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* [IndexOfRightMostSetBit](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/IndexOfRightMostSetBit.java)
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* [IndexOfRightMostSetBit](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/IndexOfRightMostSetBit.java)
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* [IsEven](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/IsEven.java)
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* [IsEven](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/IsEven.java)
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@ -658,6 +659,7 @@
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* [CountSetBitsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/CountSetBitsTest.java)
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* [CountSetBitsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/CountSetBitsTest.java)
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* [GrayCodeConversionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/GrayCodeConversionTest.java)
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* [GrayCodeConversionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/GrayCodeConversionTest.java)
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* [HammingDistanceTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/HammingDistanceTest.java)
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* [HammingDistanceTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/HammingDistanceTest.java)
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* [HigherLowerPowerOfTwoTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/HigherLowerPowerOfTwoTest.java)
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* [HighestSetBitTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/HighestSetBitTest.java)
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* [HighestSetBitTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/HighestSetBitTest.java)
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* [IndexOfRightMostSetBitTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/IndexOfRightMostSetBitTest.java)
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* [IndexOfRightMostSetBitTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/IndexOfRightMostSetBitTest.java)
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* [IsEvenTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/IsEvenTest.java)
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* [IsEvenTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/IsEvenTest.java)
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@ -0,0 +1,54 @@
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package com.thealgorithms.bitmanipulation;
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/**
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* HigherLowerPowerOfTwo class has two methods to find the next higher and lower power of two.
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* <p>
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* nextHigherPowerOfTwo method finds the next higher power of two.
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* nextLowerPowerOfTwo method finds the next lower power of two.
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* Both methods take an integer as input and return the next higher or lower power of two.
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* If the input is less than 1, the next higher power of two is 1.
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* If the input is less than or equal to 1, the next lower power of two is 0.
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* nextHigherPowerOfTwo method uses bitwise operations to find the next higher power of two.
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* nextLowerPowerOfTwo method uses Integer.highestOneBit method to find the next lower power of two.
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* The time complexity of both methods is O(1).
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* The space complexity of both methods is O(1).
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* </p>
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*
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* @author Hardvan
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*/
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public final class HigherLowerPowerOfTwo {
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private HigherLowerPowerOfTwo() {
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}
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/**
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* Finds the next higher power of two.
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*
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* @param x The given number.
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* @return The next higher power of two.
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*/
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public static int nextHigherPowerOfTwo(int x) {
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if (x < 1) {
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return 1;
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}
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x--;
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x |= x >> 1;
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x |= x >> 2;
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x |= x >> 4;
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x |= x >> 8;
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x |= x >> 16;
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return x + 1;
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}
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/**
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* Finds the next lower power of two.
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*
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* @param x The given number.
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* @return The next lower power of two.
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*/
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public static int nextLowerPowerOfTwo(int x) {
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if (x < 1) {
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return 0;
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}
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return Integer.highestOneBit(x);
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}
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}
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@ -0,0 +1,26 @@
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package com.thealgorithms.bitmanipulation;
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import static org.junit.jupiter.api.Assertions.assertEquals;
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import org.junit.jupiter.api.Test;
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public class HigherLowerPowerOfTwoTest {
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@Test
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public void testNextHigherPowerOfTwo() {
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assertEquals(32, HigherLowerPowerOfTwo.nextHigherPowerOfTwo(19)); // next higher power of two is 32
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assertEquals(1, HigherLowerPowerOfTwo.nextHigherPowerOfTwo(1)); // next higher power of two is 1
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assertEquals(16, HigherLowerPowerOfTwo.nextHigherPowerOfTwo(15)); // next higher power of two is 16
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assertEquals(8, HigherLowerPowerOfTwo.nextHigherPowerOfTwo(8)); // next higher power of two is 8
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assertEquals(16, HigherLowerPowerOfTwo.nextHigherPowerOfTwo(9)); // next higher power of two is 16
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}
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@Test
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public void testNextLowerPowerOfTwo() {
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assertEquals(16, HigherLowerPowerOfTwo.nextLowerPowerOfTwo(19)); // next lower power of two is 16
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assertEquals(1, HigherLowerPowerOfTwo.nextLowerPowerOfTwo(1)); // next lower power of two is 1
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assertEquals(8, HigherLowerPowerOfTwo.nextLowerPowerOfTwo(9)); // next lower power of two is 8
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assertEquals(8, HigherLowerPowerOfTwo.nextLowerPowerOfTwo(15)); // next lower power of two is 8
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assertEquals(8, HigherLowerPowerOfTwo.nextLowerPowerOfTwo(8)); // next lower power of two is 8
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}
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}
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