Cacher is the code snippet organizer for pro developers

public class Solution {
    public List<Integer> findDisappearedNumbers(int[] nums) {
        int i =0;
        int sum = 1;
      
        int prev = 0;
        Arrays.sort(nums);
        
        List<Integer> list = new ArrayList<>();
        
        while(i < nums.length){
           if(nums[i] == prev){
               i++;
           }
           else if(sum == nums[i]){
               prev = nums[i];
               sum++;
               i++;
           }else{
               list.add(sum);
               sum++;
           }
        }
        
        while(sum <= nums.length ){
            list.add(sum);
            sum++;
        }
        
        
        return list;
    }
}