Car Pooling Problem | Amazon Interview Question | Difference Array & Prefix Sum Explained

Facing the "Car Pooling" problem on LeetCode (Problem 1094)? You've come to the right place! In this video, I'll show you an incredibly efficient solution using the difference array technique, which is a powerful application of the prefix sum concept. 📈 This problem asks us to determine if we can accommodate all passenger trips given a car's capacity. A naive approach might be slow, especially with many trips. My solution provides a much faster way to track the number of passengers in the car at every location. Here’s the core idea: We use a difference array to mark changes in the number of passengers at each location. For each trip [num_passengers, from, to], we increment the passenger count at the from location and decrement it at the to location. Then, we compute a prefix sum on this difference array. The value at any index i will represent the total number of passengers in the car at location i. Finally, we iterate through our prefix sum array to find the maximum number of passengers at any given time and compare it with the car's capacity. This is a brilliant technique for problems involving intervals or ranges, as it simplifies tracking changes over time. It's a must-know for coding interviews! Problem Link: LeetCode Problem 1094 : https://leetcode.com/problems/car-pooling/description/ Code & Resources: GitHub Repository: https://github.com/Sanyam243/Leetcode-POTD.git Connect with me: https://www.linkedin.com/in/sanyam-jain-229052250/ #LeetCode #CarPooling #DifferenceArray #PrefixSum #CodingInterview #DataStructuresAndAlgorithms #ProblemSolving #LeetCode1094 #Cplusplus #Programming #TechInterview #DSA #algorithms