LeetCode 1511: Customer Order Frequency Solution

Master LeetCode problem 1511 (Customer Order Frequency), a easy challenge, with our optimized solutions in Java, C++, and Python. Explore detailed explanations, test your code in our interactive editor, and prepare for coding interviews.

1511. Customer Order Frequency

Easy

Database

Problem Explanation

Explanation:

To solve this problem, we need to count the frequency of each customer's orders in the given order list. We can achieve this by using a HashMap to store the count of orders for each customer. Then, we can iterate through the order list and update the count for each customer.

Algorithm:

Initialize a HashMap to store the count of orders for each customer.
Iterate through the order list.
For each order, check if the customer exists in the HashMap.
- If the customer does not exist, add the customer to the HashMap with a count of 1.
- If the customer exists, increment the count by 1.
After iterating through all orders, return the HashMap containing the frequency of orders for each customer.

Time Complexity:

The time complexity of this approach is O(n), where n is the number of orders in the order list.

Space Complexity:

The space complexity of this approach is O(n) to store the counts for each customer.

Solution Code

import java.util.*;

class Solution {
    public Map<String, Integer> countCustomerOrders(String[] orders) {
        Map<String, Integer> frequencyMap = new HashMap<>();
        
        for (String order : orders) {
            frequencyMap.put(order, frequencyMap.getOrDefault(order, 0) + 1);
        }
        
        return frequencyMap;
    }
}

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What is the time complexity of LeetCode 1511 (Customer Order Frequency)?

The time complexity for LeetCode 1511 (Customer Order Frequency) varies by solution. Check the detailed explanation section for specific complexities in Java, C++, and Python implementations.

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