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import java.io.*;
import java.lang.*;
import java.util.*;
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) {
// for debugging
// System.out.println(price);
Stock stock = backpointers.get(price).stock;
if (stock != NOTHING)
result.add(stock);
}
Collections.reverse(result);
return result;
}
public static void main(String[] args) {
int input;
Scanner scanner = new Scanner(System.in);
ArrayList<Stock> choices = new ArrayList<Stock>();
int priceLimit = 0;
boolean run = false;
do {
System.out.println("1. Add a stock");
System.out.println("2. Buying power");
System.out.println("3. Display stocks and buying power");
System.out.println("4. Run");
System.out.println("5. Exit");
input = scanner.nextInt();
String newLine = scanner.nextLine();
switch (input) {
case 1:
System.out.println("Type 'Stock Ticker, Price (USD), "
+ "Value'");
String stockInput = scanner.nextLine();
String[] stockTraits = stockInput.trim()
.split("\\s*,\\s*");
try {
choices.add(new Stock(Integer.parseInt(stockTraits[1]),
Integer.parseInt(stockTraits[2]), stockTraits[0]));
} catch (NumberFormatException e) {
System.out.println("Invalid input - must enter: "
+ "ticker, #, #");
} catch (ArrayIndexOutOfBoundsException e) {
System.out.println("Wrong number of inputs - must "
+ "enter: ticker, #, #");
}
break;
case 2:
System.out.println("How much money do you have to "
+ "allocate?");
priceLimit = Integer.parseInt(scanner.nextLine());
break;
case 3:
System.out.println(choices);
System.out.println(priceLimit);
break;
case 4:
run = true;
break;
case 5:
System.exit(0);
break;
default:
System.out.println("Invalid input - must enter a number "
+ "between 1 and 5");
break;
}
}
while(run == false);
// Stock stocks[] = {new Stock(3, 10, "A"), new Stock(4, 14, "B")};
ArrayList result = chooseStocks(choices.toArray(
new Stock[choices.size()]), priceLimit);
for (int i = 0; i < result.size(); i++) {
System.out.println(result.get(i));
}
}
}
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;
}
@Override
public String toString() {
return "Ticker: " + ticker + " price: " + price + " value: " + value;
}
}
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