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import java.util.*;
import java.io.*;
public class Stock {
int price, value;
String ticker;
public Stock() {
price = 0;
value = 0;
ticker = "";
}
public Stock(int price, int value, String ticker) {
this.price = price;
this.value = value;
this.ticker = ticker;
}
}
public class Backpointer {
static Stock NOTHING = new Stock(1, 0, "");
int previousValue, totalValue;
Stock stock;
public Backpointer(int previousValue, Stock stock) {
this.stock = stock;
this.totalValue = previousValue + stock.value;
}
public static Backpointer chooseBackpointer(Stock stocks[],
ArrayList<Backpointer> backpointers) {
int currentPrice = backpointers.size();
Backpointer best =
new Backpointer(backpointers.get(currentPrice - 1).totalValue, NOTHING);
for (int i = 0; i < stocks.length; i++) {
Stock stock = stocks[i];
int previousPrice = currentPrice - stock.price;
if (previousPrice >= 0) {
Backpointer candidate =
new Backpointer(backpointers.get(previousPrice).totalValue, stock);
if (candidate.totalValue > best.totalValue) {
best = candidate;
}
}
}
return best;
}
public static ArrayList chooseStocks(Stock stocks[], int priceLimit) {
// assert stock values are integers
// create backpointers
ArrayList<Backpointer> backpointers = new ArrayList<Backpointer>();
backpointers.add(new Backpointer(0, NOTHING));
while (backpointers.size() <= priceLimit) {
backpointers.add(chooseBackpointer(stocks, backpointers));
}
// postprocess backpointers
ArrayList<Stock> result = new ArrayList<Stock>();
for (int price = priceLimit; price > 0;
price -= backpointers.get(price).stock.price) {
Stock stock = backpointers.get(price).stock;
if (stock != NOTHING)
result.add(stock);
result.add(backpointers.get(price).stock);
}
Collections.reverse(result);
return result;
}
public static void main(String[] args) {
Stock stocks[] = {new Stock(3, 10, "A"), new Stock(4, 14, "B")};
int priceLimit = 10;
ArrayList result = chooseStocks(stocks, priceLimit);
}
}
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