YuCheng Hu
84 lines
2.2 KiB
Java
84 lines
2.2 KiB
Java
package com.ossez.codebank.interview.tests;
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import java.util.ArrayList;
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import java.util.Arrays;
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import java.util.List;
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import java.util.stream.Stream;
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import org.junit.Test;
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import org.slf4j.Logger;
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import org.slf4j.LoggerFactory;
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/**
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* PillPack
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*
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* <pre>
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* https://www.cwiki.us/display/ITCLASSIFICATION/Flatten+Nested+Arrays
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* </pre>
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*
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* @author YuCheng
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*
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*/
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public class PillPackTest {
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private final static Logger logger = LoggerFactory.getLogger(PillPackTest.class);
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List<Integer> returnList = new ArrayList<Integer>();
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/**
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* https://www.cwiki.us/display/ITCLASSIFICATION/Flatten+Nested+Arrays
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*
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* FlattenNestedArrays
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*/
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@Test
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public void testFlattenNestedArrays() {
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logger.debug("Test FlattenNestedArrays");
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Object[] array = { 1, 2, new Object[] { 3, 4, new Object[] { 5, new Object[] { new Object[] { 6 } } }, 7 }, 8, 9, 10 };
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logger.debug("LOOP: {} - > {}", Arrays.deepToString(array), Arrays.toString(loopFlatten(array)));
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logger.debug("Java 8: {} - > {}", Arrays.deepToString(array), Arrays.toString(java8Flatten(array).toArray()));
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}
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/**
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* Loop And Recursive
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*
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* @param inputArray
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* @return
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* @throws IllegalArgumentException
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*/
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private static Integer[] loopFlatten(Object[] inputArray) throws IllegalArgumentException {
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// NULL CHECK
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if (inputArray == null)
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return null;
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List<Integer> flatList = new ArrayList<Integer>();
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for (Object element : inputArray) {
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if (element instanceof Integer) {
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flatList.add((Integer) element);
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} else if (element instanceof Object[]) {
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// Recursive
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flatList.addAll(Arrays.asList(loopFlatten((Object[]) element)));
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} else {
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throw new IllegalArgumentException("Input must be an array of Integers or nested arrays of Integers");
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}
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}
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return flatList.toArray(new Integer[flatList.size()]);
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}
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/**
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* Java 8 Stream to Flatten array.
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*
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* @param array
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* @return
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*/
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private static Stream<Object> java8Flatten(Object[] array) {
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// int[] flatInt = java8Flatten(array).mapToInt(Integer.class::cast).toArray();
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return Arrays.stream(array).flatMap(o -> o instanceof Object[] ? java8Flatten((Object[]) o) : Stream.of(o));
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}
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}
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