We will sort the amounts descendingly by size, from the largest to the smallest one. For each "prefix" that consists of ~K~ richest clients, we will calculate the corresponding numbers ~A~ and ~B~, the share of that prefix in the number of accounts (~A = K / N \times 100\%~) and the total share of the money for that prefix:

$$\displaystyle B = \frac{\text{the sum of }K\text{ largest amounts}}{\text{the sum of all amounts}} \times 100\%$$

We now check if the difference ~B-A~ is the largest so far: if it is, we update the temporary variables ~A_{best}~, ~B_{best}~, the ones we output in the end.

Given the size of the array, we need to efficiently sort it, in the complexity ~\mathcal O(N \log N)~, and then efficiently calculate the sum of prefixes. The easiest way to do so is to calculate the sum of ~K~-prefix by adding the ~K^\text{th}~ element to the previously calculated ~(K-1)~-prefix.