448. Find All Numbers Disappeared in an Array

class Solution {
    public List<Integer> findDisappearedNumbers(int[] nums) { 
         
         
         int j = 0;
         while(j < nums.length){
             int correct = nums[j] - 1;
             if(nums[j] != nums[correct]){
                 swap(nums, j , correct);
             }
             else{
                 j++;
             }
         }


        List<Integer> list = new ArrayList();
        for(int i = 0;i< nums.length; i++){

                 if(nums[i] != i + 1){
                     list.add(i + 1);
                 }
         }

         return list;

        
    }

    void swap(int[] nums, int i , int correct){
        int temp  = nums[i];
        nums[i] = nums[correct];
        nums[correct] = temp;
    }
}