➡️ Interviewer: Hi, can you tell me a little bit about yourself?
👨🦰 Sideon: Hi, I'm Sideon. I have been working in the software industry for over 10 years now. I specialize in Java and have experience working with different kinds of data structures and algorithms.
➡️ Interviewer: Great, let's jump right into the question. Have you heard of the Two Sum problem on Leetcode?
👨🦰 Sideon: Yes, I have. It's a classic problem where we are given an array of integers and a target value, and we have to find two numbers in the array that add up to the target value.
➡️ Interviewer: Exactly. How would you approach this problem?
👨🦰 Sideon: Well, the brute force approach would be to loop through each element in the array and for each element, loop through the remaining elements to find a pair that adds up to the target value. This would have a time complexity of O(n^2).
➡️ Interviewer: That's correct. Do you have any other approaches in mind?
👨🦰 Sideon: Yes, we can use a hash map to store the difference between the target value and each element in the array. Then, as we loop through the array, we can check if the current element's complement exists in the hash map. If it does, we can return the indices of the two elements. This approach would have a time complexity of O(n).
➡️ Interviewer: That's a great optimization. Can you walk me through your implementation of the hash map approach in Java?
👨🦰 Sideon: Sure. Here's my implementation:
public int[] twoSum(int[] nums, int target) {
Map<Integer, Integer> map = new HashMap<>();
for (int i = 0; i < nums.length; i++) {
int complement = target - nums[i];
if (map.containsKey(complement)) {
return new int[] { map.get(complement), i };
}
map.put(nums[i], i);
}
throw new IllegalArgumentException("No two sum solution");
}
➡️ Interviewer: That looks good to me. Can you explain how you're handling edge cases and corner cases?
👨🦰 Sideon: Sure. One edge case would be if the array is empty, in which case I'm just throwing an IllegalArgumentException. Another edge case would be if there are no two elements in the array that add up to the target value, in which case the loop would end and I'm also throwing an IllegalArgumentException.
➡️ Interviewer: Good to know. Does the above code follow all the coding principles and standards?
👨🦰 Sideon: Yes, I believe so. I have used good variable names, followed proper indentation and spacing, and used appropriate exception handling.
➡️ Interviewer: Great. Is the implementation correct with all test and edge cases covered?
👨🦰 Sideon: Yes, I have tested the code with multiple test cases, including empty array and target values, and it works as expected.
➡️ Interviewer: That's great to hear. Overall, I think you did a great job with this problem. Your implementation is efficient and handles edge cases properly. One thing I would suggest is to add comments to your code to explain the thought process and logic behind each step. Keep up the good work!
😎 Keep an eye out for similar Leetcode Interview Simulations on various problems, Though we kicked off with an easy one today, always check the comments.