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Merge pull request #14775 from parthiv39731/PR-6726 

BAEL-6726, Merge Two Arrays and Remove Duplicates in Java
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davidmartinezbarua 2023-09-21 11:51:52 -03:00 committed by GitHub
parent e842b87ec5 2d4d7308ad
commit 3f62e256da
2 changed files with 170 additions and 0 deletions
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96
core-java-modules/core-java-arrays-guides/src/main/java/com/baeldung/mergeandremoveduplicate/MergeArraysAndRemoveDuplicate.java Normal file
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package com.baeldung.mergeandremoveduplicate;
import java.util.Arrays;
import java.util.HashSet;
import java.util.Set;
import java.util.stream.Stream;
public class MergeArraysAndRemoveDuplicate {
public static int[] removeDuplicateOnSortedArray(int[] arr) {
// Initialize a new array to store unique elements
int[] uniqueArray = new int[arr.length];
uniqueArray[0] = arr[0];
int uniqueCount = 1;
// Iterate through the sorted array to remove duplicates
for (int i = 1; i < arr.length; i++) {
if (arr[i] != arr[i - 1]) {
uniqueArray[uniqueCount] = arr[i];
uniqueCount++;
}
}
int[] truncatedArray = new int[uniqueCount];
System.arraycopy(uniqueArray, 0, truncatedArray, 0, uniqueCount);
return truncatedArray;
}
public static int[] mergeAndRemoveDuplicatesUsingStream(int[] arr1, int[] arr2) {
Stream<Integer> s1 = Arrays.stream(arr1).boxed();
Stream<Integer> s2 = Arrays.stream(arr2).boxed();
return Stream.concat(s1, s2)
.distinct()
.mapToInt(Integer::intValue)
.toArray();
}
public static int[] mergeAndRemoveDuplicatesUsingSet(int[] arr1, int[] arr2) {
int[] mergedArr = mergeArrays(arr1, arr2);
Set<Integer> uniqueInts = new HashSet<>();
for (int el : mergedArr) {
uniqueInts.add(el);
}
return getArrayFromSet(uniqueInts);
}
private static int[] getArrayFromSet(Set<Integer> set) {
int[] mergedArrWithoutDuplicated = new int[set.size()];
int i = 0;
for (Integer el: set) {
mergedArrWithoutDuplicated[i] = el;
i++;
}
return mergedArrWithoutDuplicated;
}
public static int[] mergeAndRemoveDuplicates(int[] arr1, int[] arr2) {
return removeDuplicate(mergeArrays(arr1, arr2));
}
public static int[] mergeAndRemoveDuplicatesOnSortedArray(int[] arr1, int[] arr2) {
return removeDuplicateOnSortedArray(mergeArrays(arr1, arr2));
}
private static int[] mergeArrays(int[] arr1, int[] arr2) {
int[] mergedArrays = new int[arr1.length + arr2.length];
System.arraycopy(arr1, 0, mergedArrays, 0, arr1.length);
System.arraycopy(arr2, 0, mergedArrays, arr1.length, arr2.length);
return mergedArrays;
}
private static int[] removeDuplicate(int[] arr) {
int[] withoutDuplicates = new int[arr.length];
int i = 0;
for(int element : arr) {
if(!isElementPresent(withoutDuplicates, element)) {
withoutDuplicates[i] = element;
i++;
}
}
int[] truncatedArray = new int[i];
System.arraycopy(withoutDuplicates, 0, truncatedArray, 0, i);
return truncatedArray;
}
private static boolean isElementPresent(int[] arr, int element) {
for(int el : arr) {
if(el == element) {
return true;
}
}
return false;
}
}

74
core-java-modules/core-java-arrays-guides/src/test/java/com/baeldung/mergeandremoveduplicate/MergeArraysAndRemoveDuplicateUnitTest.java Normal file
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package com.baeldung.mergeandremoveduplicate;
import org.junit.jupiter.api.Test;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.util.Arrays;
import java.util.stream.Collectors;
import static org.junit.jupiter.api.Assertions.assertArrayEquals;
public class MergeArraysAndRemoveDuplicateUnitTest {
private final Logger logger = LoggerFactory.getLogger(MergeArraysAndRemoveDuplicateUnitTest.class);
private static String getCommaDelimited(int[] arr) {
return Arrays.stream(arr)
.mapToObj(Integer::toString)
.collect(Collectors.joining(", "));
}
@Test
public void givenNoLibraryAndUnSortedArrays_whenArr1andArr2_thenMergeAndRemoveDuplicates() {
int[] arr1 = {3, 2, 1, 4, 5, 6, 8, 7, 9};
int[] arr2 = {8, 9, 10, 11, 12, 13, 15, 14, 15, 14, 16, 17};
int[] expectedArr = {3, 2, 1, 4, 5, 6, 8, 7, 9, 10, 11, 12, 13, 15, 14, 16, 17};
int[] mergedArr = MergeArraysAndRemoveDuplicate.mergeAndRemoveDuplicates(arr1, arr2);
//merged array maintains the order of the elements in the arrays
assertArrayEquals(expectedArr, mergedArr);
logger.info(getCommaDelimited(mergedArr));
}
@Test
public void givenNoLibraryAndSortedArrays_whenArr1andArr2_thenMergeAndRemoveDuplicates() {
int[] arr1 = {1, 2, 3, 4, 5, 5, 6, 7, 7, 8};
int[] arr2 = {8, 9, 10, 11, 12, 13, 14, 15, 15, 16, 17};
int[] expectedArr = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17};
int[] mergedArr = MergeArraysAndRemoveDuplicate.mergeAndRemoveDuplicatesOnSortedArray(arr1, arr2);
assertArrayEquals(expectedArr, mergedArr);
logger.info(getCommaDelimited(mergedArr));
}
@Test
public void givenSet_whenArr1andArr2_thenMergeAndRemoveDuplicates() {
int[] arr1 = {3, 2, 1, 4, 5, 6, 8, 7, 9};
int[] arr2 = {8, 9, 10, 11, 12, 13, 15, 14, 15, 14, 16, 17};
int[] expectedArr = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17};
int[] mergedArr = MergeArraysAndRemoveDuplicate.mergeAndRemoveDuplicatesUsingSet(arr1, arr2);
assertArrayEquals(expectedArr, mergedArr);
logger.info(getCommaDelimited(mergedArr));
}
@Test
public void givenStream_whenArr1andArr2_thenMergeAndRemoveDuplicates() {
int[] arr1 = {3, 2, 1, 4, 5, 6, 8, 7, 9};
int[] arr2 = {8, 9, 10, 11, 12, 13, 15, 14, 15, 14, 16, 17};
int[] expectedArr = {3, 2, 1, 4, 5, 6, 8, 7, 9, 10, 11, 12, 13, 15, 14, 16, 17};
int[] mergedArr = MergeArraysAndRemoveDuplicate.mergeAndRemoveDuplicatesUsingStream(arr1, arr2);
assertArrayEquals(expectedArr, mergedArr);
logger.info(getCommaDelimited(mergedArr));
}
}