diff --git a/DIRECTORY.md b/DIRECTORY.md index 10922d761952..b7707a254ab6 100644 --- a/DIRECTORY.md +++ b/DIRECTORY.md @@ -320,11 +320,14 @@ * [BresenhamLine](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/geometry/BresenhamLine.java) * [ConvexHull](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/geometry/ConvexHull.java) * [GrahamScan](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/geometry/GrahamScan.java) + * [MidpointCircle](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/geometry/MidpointCircle.java) + * [MidpointEllipse](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/geometry/MidpointEllipse.java) * [Point](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/geometry/Point.java) * graph * [StronglyConnectedComponentOptimized](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/graph/StronglyConnectedComponentOptimized.java) * greedyalgorithms * [ActivitySelection](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/ActivitySelection.java) + * [BandwidthAllocation](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/BandwidthAllocation.java) * [BinaryAddition](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/BinaryAddition.java) * [CoinChange](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/CoinChange.java) * [DigitSeparation](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/DigitSeparation.java) @@ -360,6 +363,7 @@ * [Average](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/Average.java) * [BinaryPow](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/BinaryPow.java) * [BinomialCoefficient](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/BinomialCoefficient.java) + * [CatalanNumbers](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/CatalanNumbers.java) * [Ceil](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/Ceil.java) * [ChineseRemainderTheorem](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/ChineseRemainderTheorem.java) * [CircularConvolutionFFT](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/CircularConvolutionFFT.java) @@ -967,10 +971,13 @@ * [BresenhamLineTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/geometry/BresenhamLineTest.java) * [ConvexHullTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/geometry/ConvexHullTest.java) * [GrahamScanTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/geometry/GrahamScanTest.java) + * [MidpointCircleTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/geometry/MidpointCircleTest.java) + * [MidpointEllipseTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/geometry/MidpointEllipseTest.java) * graph * [StronglyConnectedComponentOptimizedTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/graph/StronglyConnectedComponentOptimizedTest.java) * greedyalgorithms * [ActivitySelectionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/ActivitySelectionTest.java) + * [BandwidthAllocationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/BandwidthAllocationTest.java) * [BinaryAdditionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/BinaryAdditionTest.java) * [CoinChangeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/CoinChangeTest.java) * [DigitSeparationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/DigitSeparationTest.java) @@ -1003,6 +1010,7 @@ * [AverageTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/AverageTest.java) * [BinaryPowTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/BinaryPowTest.java) * [BinomialCoefficientTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/BinomialCoefficientTest.java) + * [CatalanNumbersTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/CatalanNumbersTest.java) * [CeilTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/CeilTest.java) * [ChineseRemainderTheoremTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/ChineseRemainderTheoremTest.java) * [CollatzConjectureTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/CollatzConjectureTest.java) diff --git a/src/main/java/com/thealgorithms/greedyalgorithms/BandwidthAllocation.java b/src/main/java/com/thealgorithms/greedyalgorithms/BandwidthAllocation.java new file mode 100644 index 000000000000..602cdcd5ad40 --- /dev/null +++ b/src/main/java/com/thealgorithms/greedyalgorithms/BandwidthAllocation.java @@ -0,0 +1,58 @@ +package com.thealgorithms.greedyalgorithms; + +import java.util.Arrays; + +/** + * Class to solve the Bandwidth Allocation Problem. + * The goal is to maximize the value gained by allocating bandwidth to users. + * Example: + * Bandwidth = 10 + * Users = [3, 5, 7] + * Values = [10, 20, 30] + * The maximum value achievable is 40 by allocating 3 units to user 0 and 7 units to user 2. + * + * @author Hardvan + */ +public final class BandwidthAllocation { + private BandwidthAllocation() { + } + + /** + * Allocates bandwidth to maximize value. + * Steps: + * 1. Calculate the ratio of value/demand for each user. + * 2. Sort the users in descending order of the ratio. + * 3. Allocate bandwidth to users in order of the sorted list. + * 4. If the bandwidth is not enough to allocate the full demand of a user, allocate a fraction of the demand. + * 5. Return the maximum value achievable. + * + * @param bandwidth total available bandwidth to allocate + * @param users array of user demands + * @param values array of values associated with each user's demand + * @return the maximum value achievable + */ + public static int maxValue(int bandwidth, int[] users, int[] values) { + int n = users.length; + double[][] ratio = new double[n][2]; // {index, ratio} + + for (int i = 0; i < n; i++) { + ratio[i][0] = i; + ratio[i][1] = (double) values[i] / users[i]; + } + + Arrays.sort(ratio, (a, b) -> Double.compare(b[1], a[1])); + + int maxValue = 0; + for (int i = 0; i < n; i++) { + int index = (int) ratio[i][0]; + if (bandwidth >= users[index]) { + maxValue += values[index]; + bandwidth -= users[index]; + } else { + maxValue += (int) (ratio[i][1] * bandwidth); + break; + } + } + return maxValue; + } +} diff --git a/src/test/java/com/thealgorithms/greedyalgorithms/BandwidthAllocationTest.java b/src/test/java/com/thealgorithms/greedyalgorithms/BandwidthAllocationTest.java new file mode 100644 index 000000000000..452f7858c162 --- /dev/null +++ b/src/test/java/com/thealgorithms/greedyalgorithms/BandwidthAllocationTest.java @@ -0,0 +1,22 @@ +package com.thealgorithms.greedyalgorithms; + +import static org.junit.jupiter.api.Assertions.assertEquals; + +import java.util.stream.Stream; +import org.junit.jupiter.params.ParameterizedTest; +import org.junit.jupiter.params.provider.Arguments; +import org.junit.jupiter.params.provider.MethodSource; + +public class BandwidthAllocationTest { + + @ParameterizedTest + @MethodSource("bandwidthProvider") + public void testMaxValue(int capacity, int[] bandwidths, int[] values, int expected) { + assertEquals(expected, BandwidthAllocation.maxValue(capacity, bandwidths, values)); + } + + private static Stream bandwidthProvider() { + return Stream.of(Arguments.of(50, new int[] {20, 10, 30}, new int[] {40, 20, 30}, 80), Arguments.of(0, new int[] {5, 10}, new int[] {10, 20}, 0), Arguments.of(5, new int[] {5, 10}, new int[] {10, 20}, 10), Arguments.of(15, new int[] {10, 20}, new int[] {10, 25}, 18), + Arguments.of(25, new int[] {10, 15, 20}, new int[] {10, 30, 50}, 60)); + } +}