import java.util.*; public class Solution { /** * 代码中的类名、方法名、参数名已经指定,请勿修改,直接返回方法规定的值即可 * * * @param nums int整型一维数组 * @return int整型一维数组 */ public int[] findDisappearedNumbers (int[] nums) { // write code here List<Integer> list = new ArrayList<>(); HashSet<Integer> hashSet = new HashSet<>(); for (int i = 0; i < nums.length; i++) { hashSet.add(nums[i]); } for (int i = 1; i <= nums.length; i++) { if (!hashSet.contains(i)) { list.add(i); } } //List<Integer> ==>转 int[] int[] ints = list.stream().mapToInt(Integer::valueOf).toArray(); return ints; } }