arr by absolute values.count to store the frequency of each element in arr.x, check if count[x] is greater than 0.
b. If so, check if count[2*x] is also greater than 0.
c. If both counts are positive, decrement count[x] and count[2*x] by 1.
d. If count[2*x] is not positive, return false as we cannot pair x with 2*x.false, return true.