LeetCode 1596: The Most Frequently Ordered Products for Each Customer
Problem Description
Explanation:
To solve this problem, we can iterate through the given order data and maintain a map to store the frequency of products ordered by each customer. We can then find the most frequently ordered products for each customer and return the result.
- Create a hashmap to store the frequency of products ordered by each customer.
- Iterate through the orders data and update the frequency of each product for each customer.
- For each customer, find the most frequently ordered products and store them in the result list.
- Return the result list.
Time Complexity: O(N), where N is the total number of orders. Space Complexity: O(N), for the hashmap and result list.
: :
Solutions
import java.util.*;
class Solution {
public List<List<String>> mostFrequentProducts(List<List<String>> orders) {
Map<String, Map<String, Integer>> freqMap = new HashMap<>();
for (List<String> order : orders) {
String customer = order.get(0);
String product = order.get(1);
if (!freqMap.containsKey(customer)) {
freqMap.put(customer, new HashMap<>());
}
freqMap.get(customer).put(product, freqMap.get(customer).getOrDefault(product, 0) + 1);
}
List<List<String>> result = new ArrayList<>();
for (String customer : freqMap.keySet()) {
List<String> mostFrequent = new ArrayList<>();
int maxFreq = 0;
for (String product : freqMap.get(customer).keySet()) {
int freq = freqMap.get(customer).get(product);
if (freq > maxFreq) {
mostFrequent.clear();
mostFrequent.add(product);
maxFreq = freq;
} else if (freq == maxFreq) {
mostFrequent.add(product);
}
}
result.add(mostFrequent);
}
return result;
}
}Loading editor...