Add FindMaxRecursionTest (#4431)
* Update FindMaxRecursion.java * Create FindMaxRecusionTest.java * Update and rename FindMaxRecusionTest.java to FindMaxRecursionTest.java * Update FindMaxRecursion.java * Update FindMaxRecursion.java * Update src/test/java/com/thealgorithms/maths/FindMaxRecursionTest.java Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com> * Update src/test/java/com/thealgorithms/maths/FindMaxRecursionTest.java Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com> * Update src/main/java/com/thealgorithms/maths/FindMaxRecursion.java Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com> * Update FindMaxRecursion.java * Update FindMaxRecursionTest.java * Update FindMaxRecursionTest.java * Update FindMaxRecursion.java * Update src/main/java/com/thealgorithms/maths/FindMaxRecursion.java Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com> * Update FindMaxRecursion.java * Update FindMaxRecursion.java * Update FindMaxRecursion.java * Update FindMaxRecursion.java * Update FindMaxRecursion.java * Update src/main/java/com/thealgorithms/maths/FindMaxRecursion.java Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com> --------- Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>
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@ -1,26 +1,9 @@
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package com.thealgorithms.maths;
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package com.thealgorithms.maths;
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import java.util.Arrays;
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public final class FindMaxRecursion {
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import java.util.Random;
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public class FindMaxRecursion {
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private FindMaxRecursion() {
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public static void main(String[] args) {
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Random rand = new Random();
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/* rand size */
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int size = rand.nextInt(100) + 1;
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int[] array = new int[size];
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/* init array with rand numbers */
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for (int i = 0; i < size; i++) {
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array[i] = rand.nextInt() % 100;
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}
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assert max(array) == Arrays.stream(array).max().getAsInt();
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assert max(array, 0, array.length - 1) == Arrays.stream(array).max().getAsInt();
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}
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}
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/**
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/**
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* Get max of array using divide and conquer algorithm
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* Get max of array using divide and conquer algorithm
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*
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*
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@ -29,7 +12,10 @@ public class FindMaxRecursion {
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* @param high the index of the last element
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* @param high the index of the last element
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* @return max of {@code array}
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* @return max of {@code array}
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*/
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*/
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public static int max(int[] array, int low, int high) {
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public static int max(final int[] array, final int low, final int high) {
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if (array.length == 0) {
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throw new IllegalArgumentException("array must be non-empty.");
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}
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if (low == high) {
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if (low == high) {
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return array[low]; // or array[high]
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return array[low]; // or array[high]
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}
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}
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@ -48,7 +34,7 @@ public class FindMaxRecursion {
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* @param array contains elements
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* @param array contains elements
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* @return max value of {@code array}
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* @return max value of {@code array}
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*/
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*/
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public static int max(int[] array) {
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public static int max(final int[] array) {
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return array.length == 1 ? array[0] : max(array, 0, array.length);
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return max(array, 0, array.length - 1);
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}
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}
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}
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}
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@ -0,0 +1,28 @@
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package com.thealgorithms.maths;
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import static org.junit.jupiter.api.Assertions.assertThrows;
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import java.util.stream.Stream;
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import org.junit.jupiter.api.Assertions;
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import org.junit.jupiter.api.Test;
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import org.junit.jupiter.params.ParameterizedTest;
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import org.junit.jupiter.params.provider.Arguments;
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import org.junit.jupiter.params.provider.MethodSource;
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public class FindMaxRecursionTest {
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@ParameterizedTest
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@MethodSource("inputStream")
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void numberTests(int expected, int[] input) {
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Assertions.assertEquals(expected, FindMaxRecursion.max(input));
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}
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private static Stream<Arguments> inputStream() {
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return Stream.of(Arguments.of(5, new int[] {5, 5, 5, 5, 5}), Arguments.of(0, new int[] {-1, 0}), Arguments.of(-1, new int[] {-10, -9, -8, -7, -6, -5, -4, -3, -2, -1}), Arguments.of(9, new int[] {3, -2, 3, 9, -4, -4, 8}), Arguments.of(3, new int[] {3}));
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}
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@Test
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public void testFindMaxThrowsExceptionForEmptyInput() {
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assertThrows(IllegalArgumentException.class, () -> FindMaxRecursion.max(new int[] {}));
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}
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}
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