Shopify VO 面试真题解析：Calculate Shipping Cost（按国家与数量计算运费）

Calculate Shipping Cost

Order:

{
  "country": "US", // or "CA" for the CA order
  "items": [{ "product": "mouse", "quantity": 20},
    {"product": "laptop", "quantity": 5}
  ]
}

Note: In your solution, you can pass in an in-memory object that has the same shape as the JSON. You don’t need to worry about parsing JSON for this problem.

The US and CA orders have the same shape; they are just different countries.

Each country/product has a corresponding shipping cost matrix. The cost is stored in the smallest currency unit.

Shipping Cost:

Each product has its own shipping cost

{
  "US": [{ "product": "mouse", "cost": 550},
    {"product": "laptop", "cost": 1000}
  ],
  "CA": [{ "product": "mouse", "cost": 750},
    {"product": "laptop", "cost": 1100}
  ]
}

Write a function called calculate_shipping_cost that takes an order and shipping cost matrix and returns the shipping cost.

Examples:

calculate_shipping_cost(order_us, shipping_cost) == 16000
calculate_shipping_cost(order_ca, shipping_cost) == 20500

这道题要求根据订单中的国家、商品和数量，结合对应国家的运费表计算总运费。核心做法是先按国家找到该国的商品运费，再按商品名建立快速查询结构，遍历订单 items 时把每个商品的单价乘以数量累加即可。题目里金额使用最小货币单位，所以直接做整数加法，不需要处理小数；示例中 US 和 CA 的同一商品单价不同，因此要先区分 country 再计算。