A game with 100 oponnents, win as much money as possible - algorithm

Question

You play a game with 100 opponents. The game has k rounds. Every round you can eliminate some opponents (always atleast 1). You are rewarded for eliminating them.
The reward is: 100.000 * '# of eliminated opponents' / '# of opponents' <= in integers (rounded down)
I want to eliminate the opponents in a way, that gets me the largest amount of money possible.
Example game:
number of rounds = 3
first round we eliminate 50 opponents, so we get 100.000 * 50 / 100 = +50.000
second round we eliminate 30, so we get 100.000 * 30 / 50 = +60.000
last round we eliminate last 20 opponents, so we get 100.000 * 20 / 20 = +100.000
so the total winnings are: 210.000
I tried to write up something, but I don't think it's the most effective way to do it?
Program EliminationGame;
var
selectedHistory : array [1..10] of integer;
opponentCount,roundCount : integer;
maxOpponents,numberSelected : integer;
totalMoney : integer;
i : integer;
begin
totalMoney := 0;
maxOpponents := 100;
opponentCount := maxOpponents;
roundCount := 3; {test value}
for i:=1 to roundCount do begin
if (i = roundCount) then begin
numberSelected := opponentCount;
end else begin
numberSelected := floor(opponentCount / roundCount);
end;
selectedHistory[i] := numberSelected;
totalMoney := floor(totalMoney + (numberSelected / opponentCount * 100000));
opponentCount := opponentCount - numberSelected;
end;
writeln('Total money won:');
writeln(totalMoney);
writeln('Amount selected in rounds:');
for i:= 0 to Length(selectedHistory) do
write(selectedHistory[i],' ');
end.
Also it seems that floor function does not exist in pascal?

Answer 1

It seems the question has a maths answer that can be calculated in advance. As #Anton said it was obvious that the number of points given during the third round did not depend upon the number of eliminated enemies. So the third round should eliminate 1 enemy.
So We get the following function for a thre-round game.
f(x)=100000x/100+100000(99-x)/(100-x)+100000*1/1, where x- the number
of enemies eleminated at first round.
if we find the extrema (local maximum of the function) it appears equal to 90. That means the decision is the following: the first round eliminates 90 the second - 9, the third - 1 enemy.
Of course, for consideration: 90=100-sqrt(100).
In other words: the Pascal decision of the task is to loop a variable from 1 to 99 and see the maximum of this function. X-will be the answer.
program Project1;
var
x, xmax: byte;
MaxRes, tmp: real;
begin
xmax := 0;
MaxRes := 0;
for x := 1 to 99 do
begin
tmp := 100000 * x / 100 + 100000*(99 - x) / (100 - x) + 100000 * 1 / 1;
if tmp > MaxRes then
begin
MaxRes := tmp;
xmax := x;
end;
end;
writeln(xmax);
readln;
end.
The general decision for other number of enemies and rounds (using recursion) is the following (Delphi dialect):
program Project1;
{$APPTYPE CONSOLE}
{$R *.res}
Uses System.SysUtils;
var
s: string;
function Part(RemainingEnemies: byte; Depth: byte;
var OutputString: string): real;
var
i: byte;
tmp, MaxRes: real;
imax: byte;
DaughterString: string;
begin
OutputString := '';
if Depth = 0 then
exit(0);
imax := 0;
MaxRes := 0;
for i := 1 to RemainingEnemies - Depth + 1 do
begin
tmp := i / RemainingEnemies * 100000 + Part(RemainingEnemies - i, Depth - 1,
DaughterString);
if tmp > MaxRes then
begin
MaxRes := tmp;
imax := i;
OutputString := inttostr(imax) + ' ' + DaughterString;
end;
end;
result := MaxRes;
end;
begin
writeln(Part(100, 3, s):10:1);//first parameter-Enemies count,
//2-Number of rounds,
//3-output for eliminated enemies counter
writeln(s);
readln;
end.

Answer 2

This problem can be solved with a dynamic approach.
F(round,number_of_opponents_remained):
res = 0
opp // number_of_opponents_remained
for i in [1 opp]
res = max(res, opp/100 + F(round-1,opp - i) )
return res
I should say this not the complete solution and you add some details about it, and I am just giving you an idea. You should add some details such as base case and checking if opp>0 and some other details. The complexity of this algorithm is O(100*k).