Checkout Facade

The facade pattern gives a simple entry point to a complicated subsystem. A shop's checkout call hides two subsystems: the inventory and the price list.

Items are numbered 0 to n − 1. stock[i] is how many units of item i are available and prices[i] is its price. The cart is a list of [item, quantity] lines; the same item may appear on several lines.

checkout(stock, prices, cart) must:

1. Check the inventory: if the total quantity of any item in the cart is greater than its stock, the order fails.
2. Otherwise return the total price of the cart.

Implement checkout_facade(stock, prices, cart).

Input

stock, prices: n values each.

cart: [item, quantity] lines.

Output

Return the total price, or -1 if any item does not have enough stock.

制約

1 ≤ n ≤ 1,000

0 ≤ stock[i], prices[i] ≤ 100,000; 0 ≤ cart lines ≤ 1,000; 1 ≤ quantity ≤ 1,000

例

入力：
cart = [
    [0, 2],
    [2, 4]
]
stock = [5, 2, 10]
prices = [3, 20, 1]

期待される出力：
expected = 10

入力：
std::vector<std::vector<long long>> cart = {
    {0, 2},
    {2, 4}
};
std::vector<long long> stock = {5, 2, 10};
std::vector<long long> prices = {3, 20, 1};

期待される出力：
long long expected = 10;

入力：
long[][] cart = new long[][] {
    new long[] {0, 2},
    new long[] {2, 4}
};
long[] stock = new long[] {5, 2, 10};
long[] prices = new long[] {3, 20, 1};

期待される出力：
long expected = 10;

入力：
cart = [
    [1, 1],
    [1, 2]
]
stock = [5, 2]
prices = [3, 20]

期待される出力：
expected = -1

入力：
std::vector<std::vector<long long>> cart = {
    {1, 1},
    {1, 2}
};
std::vector<long long> stock = {5, 2};
std::vector<long long> prices = {3, 20};

期待される出力：
long long expected = -1;

入力：
long[][] cart = new long[][] {
    new long[] {1, 1},
    new long[] {1, 2}
};
long[] stock = new long[] {5, 2};
long[] prices = new long[] {3, 20};

期待される出力：
long expected = -1;

参考資料

この課題はCodeUtility用に調整されています。上記の説明と制約に従ってください。

• Refactoring.Guru, Design Patterns
• Gamma, Helm, Johnson, Vlissides, Design Patterns: Elements of Reusable Object-Oriented Software