Compare 2 lists to find an equal or approximate match without doing N^2 iteration

[ab231189]

I have two lists:
list1:[101,110,136]
list2:[101.04,264.5,379.9,466.4,629.6,724.4,799.8,914.3]

iterate over list1:
compare each element in this list with the elements in the list2,
if there is a number encountered in the 2nd list which is an exact match or an approximate match to the element in list1 then output that match

Note: I want to avoid the N^2 iteration strictly as I want to do it as efficiently as possible; also in all cases I sort both the lists hence both are in ascending order always.

Output should be: 101 and 101.04

[anmoluppal]

hmmmmm ..... I have thought of an algorithm that could be very efficient but it would take some time to develop a working code for that ... I hope you have enough time ... would let you know ASAP if that algo would be implemented efficiently by me .....

[dwblas]

which is an exact match or an approximate match

For an exact match, using sets and subset is the most efficient way. You do not define "approximate" though so there is no way to go further.