1. Person walks up with trash in hand to 3 bins. Each bin has a poster with pictures of items which are meant for that bin. Each person has to make O(n) comparisons for each of the bin and then make the closest judgment call. Too exhausting, error prone and inefficient as each person is solving the classification problem for a given trash item over and over again.
Here's a simple solution to the problem above:
1. Setup a regulation that each article be simply labelled with a numeral marking: "1", "2" or "3". Standardize each trash bin to be called bin #1, #2 or #3. Each person simply throws the trash in the matching bin.
This moves the classification problem from the person to the time of manufacturing of the article. Also, the classification is only done once by experts and not by each person at the time of throwing away the article. Also, reduces the classification problem for the person from O(n) to O(1).
Simple solution which solves the problem in elegant fashion.