No448.java

packageAlgorithm.leetcode.Array;

importjava.util.ArrayList;
importjava.util.HashSet;
importjava.util.List;
importjava.util.Set;

/**
 * 
 * Created by tujietg on Nov 8, 2019
 */
publicclassNo448 {
publicstaticList<Integer> findDisappearedNumbers(int[] nums) {
List<Integer> list = newArrayList<Integer>();
Set<Integer> hashSet = newHashSet<Integer>();

for (inti = 0; i < nums.length; i++) {
hashSet.add(nums[i]);
 }
intn = nums.length;
for (inti = 1; i <= n; i++) {
if (!hashSet.contains(i)) {
list.add(i);
 }
 }
returnlist;
 }

publicstaticvoidmain(String[] args) {
int[] param = newint[] { 4, 3, 2, 7, 8, 2, 3, 1 };
findDisappearedNumbers(param);
 }
}