import java.util.*;
class Main{
    public static boolean find(int [] arr,int x){
        HashSet<Integer> set=new HashSet<>();
        for(int i=0;i<arr.length;i++){
            int temp=x-arr[i];
            if(set.contains(temp)){
                return true;
            }
            set.add(arr[i]);
        }
        return false;
    }
    public static void main (String[] args) {
        int [] arr={1,2,3,4,5};
        int x=4;
        if(find(arr,x)){
            System.out.println("exist");
        }else{
            System.out.println("does'nt exist");
        }
 
    }
}

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