Final: Shop Stock Keeper

Lab Java Intermediate 20 points

Keep a shop's stock. Commands: add item qty adds stock; sell item qty sells if there is enough, otherwise prints not enough item and sells nothing; report prints every item that is in stock as item:qty in alphabetical order, separated by spaces (or empty).

Input

Line 1: q. Then q commands.

Output

Messages and reports, one per line.

Example

Input

7
add pen 10
add apple 3
sell pen 4
sell apple 5
report
sell apple 3
report

Output

not enough apple
apple:3 pen:6
pen:6

Sample input available Sample output available

Editor

Java

Hints

A TreeMap keeps items in alphabetical order for the report.

Remove an item when its stock reaches 0 so it doesn't appear in the report.

Solution explanation

Every command is O(log n) with a TreeMap; a report is O(n). A HashMap would need sorting on every report.

Show solution

import java.util.Map;
import java.util.Scanner;
import java.util.TreeMap;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int q = sc.nextInt();
        TreeMap<String, Integer> stock = new TreeMap<String, Integer>();
        StringBuilder out = new StringBuilder();
        for (int i = 0; i < q; i++) {
            String cmd = sc.next();
            if (cmd.equals("add")) {
                String item = sc.next();
                stock.put(item, stock.getOrDefault(item, 0) + sc.nextInt());
            } else if (cmd.equals("sell")) {
                String item = sc.next();
                int qty = sc.nextInt();
                int have = stock.getOrDefault(item, 0);
                if (have < qty) {
                    out.append("not enough ").append(item).append('\n');
                } else if (have == qty) {
                    stock.remove(item);
                } else {
                    stock.put(item, have - qty);
                }
            } else {
                StringBuilder line = new StringBuilder();
                for (Map.Entry<String, Integer> e : stock.entrySet()) {
                    if (line.length() > 0) line.append(' ');
                    line.append(e.getKey()).append(':').append(e.getValue());
                }
                out.append(line.length() == 0 ? "empty" : line.toString()).append('\n');
            }
        }
        System.out.print(out);
    }
}

Output

Answer