java定义俩个int类型数组求交集并集

可以使用Java中的Set集合来求解数组的交集和并集。

求交集：

int[] arr1 = {1, 2, 3, 4};
int[] arr2 = {3, 4, 5, 6};

Set<Integer> set1 = new HashSet<Integer>();
for (int i = 0; i < arr1.length; i++) {
    set1.add(arr1[i]);
}

Set<Integer> set2 = new HashSet<Integer>();
for (int i = 0; i < arr2.length; i++) {
    set2.add(arr2[i]);
}

set1.retainAll(set2);

int[] intersection = new int[set1.size()];
int index = 0;
for (Integer i : set1) {
    intersection[index++] = i;
}

System.out.println(Arrays.toString(intersection)); // 输出 [3, 4]

求并集：

int[] arr1 = {1, 2, 3, 4};
int[] arr2 = {3, 4, 5, 6};

Set<Integer> set1 = new HashSet<Integer>();
for (int i = 0; i < arr1.length; i++) {
    set1.add(arr1[i]);
}

Set<Integer> set2 = new HashSet<Integer>();
for (int i = 0; i < arr2.length; i++) {
    set2.add(arr2[i]);
}

set1.addAll(set2);

int[] union = new int[set1.size()];
int index = 0;
for (Integer i : set1) {
    union[index++] = i;
}

System.out.println(Arrays.toString(union)); // 输出 [1, 2, 3, 4, 5, 6]