Getting the lowest possible sum from numbers' difference

Question

I have to find the lowest possible sum from numbers\' difference.

Let\'s say I have 4 numbers. 1515, 1520, 1500 and 1535. The lowest sum of difference is 30, becaus

Answer 1

Something like

1. Sort List
2. Find Duplicates
3. Make the duplicates a pair
4. remove duplicates from list
5. break rest of list into pairs
6. calculate differences of each pair
7. take lowest amounts

In your example you have 8 number and need the best 3 pairs. First sort the list which gives you

1561, 1572, 1572, 1609, 1682, 1731, 1731, 2041

If you have duplicates make them a pair and remove them from the list so you have

[1572, 1572] = 0
[1731, 1731] = 0
L = { 1561, 1609, 1682, 2041 }

Break the remaining list into pairs, giving you the 4 following pairs

[1572, 1572] = 0
[1731, 1731] = 0
[1561, 1609] = 48
[1682, 2041] = 359

Then drop the amount of numbers you need to.

This gives you the following 3 pairs with the lowest pairs

[1572, 1572] = 0
[1731, 1731] = 0
[1561, 1609] = 48

So

0 + 0 + 48 = 48