448. 找到所有数组中消失的数字

https://leetcode-cn.com/problems/find-all-numbers-disappeared-in-an-array/

• 哈希表

class Solution {
    
    public List<Integer> findDisappearedNumbers(int[] nums) {
         List<Integer> res = new ArrayList<>();
        Map<Integer,Boolean> map = new HashMap<>();
        for(int num:nums){
           map.put(num,true);
        }
        for(int i=1;i<=nums.length;i++){
            if(!map.containsKey(i)){
                res.add(i);
            }
        }
        return res;
    }
}