Generate all unique combinations of Items
algorithm, combinations, java, unique
Solution
If you have N items, count from 1 to 2^N-1. Each number represents a combination, like so: if bit 0 (the least significant bit) is set, item1 is in the combination. If bit 1 is set, item2 is in the combination, and so on.
If you don't want 1-item combinations, start counting at 3, and ignore all the combinations that are a power of 2 (4, 8, 16, etc...).
Problem
I trying to generate all possible unique combination of items. ``` Ex: item1, item2, item3 Combinations: item1+item2+item3 item1+item2 item1+item3 item2+item3 item1 item2 item3 ``` I am unable to get an idea on how to solve this? ``` for(int i=0;i<size;i++){ for(int j=i+1;j<size;j++){ System.out.println(list.item(i)+list.item(j)); } } ``` The above code certainly works for all unique combination of two elements. But not for 3 element pair and more..