def get_pair_with_sum(a, need):
  s= set()
  for i in a:
    if (need- i) in s:
      print(need-i, i)
    else:
      s.add(i)

a=[4,2,4,2]
b=[3,6,2,5]
need= 8

# find subset with sum = 8
get_pair_with_sum(a, need)  #prints [4,4]
print()
get_pair_with_sum(b, need)  #prints [6,2], [3,5]