For smaller size arrays , perform brute force
for ( int i = 0 ; i < n ; i ++ ) for ( int j = i + 1 ; j < n ; j ++ ) for ( int k = j + 1 ; k < n ; k ++ ) for ( int l = k + 1 ; l < n ; l ++ ) { if ( ( arr [ i ] ^ arr [ j ] ^ arr [ k ] ^ arr [ l ] ) == 0 ) { return true ; } } return false ; }