More efficient way to build sum than for loop

Question

I have two lists with equal size. Both contain numbers. The first list is generated and the second one is static. Since I have many of the generated lists, I want to find out wh

Answer 1

This is possible without using lists. Instead of filling your two lists you just want to have the sum of each values for a single list, e.g. IList combination becomes int combinationSum.

Do the same for histDates list.

Then substract those two values. No loop in this case is needed.