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Code Problem / Data Structures and Algorithms DifficultyMedium JavaScript
Given an array of integers and a target value, return the indices of the two array elements that add up to the target value. Assume that each input will have only one solution, and that the same array element cannot be used twice.
About this solution: The candidate's solution is correct and demonstrates a level of completeness. The candidate's approach is also correct, using a hash table to store the numbers and their indices. This solution is optimal because it is O(n) time complexity and O(n) space complexity.
Dec 10
Code Problem / Data Structures and Algorithms DifficultyMedium Python
Given a set of distinct integers, this algorithm will return all possible subsets of those integers.
About this solution: The candidate's solution is a recursive function that takes in the input array and the current subset. The function iterates through the input array and adds each element to the current subset. It then calls itself with the input array and the new subset. The function also calls itself with the input array and the current subset. This allows the function to create all possible subsets. The function returns a list of all possible subsets. The function also adds the empty set to the list of subsets. The solution is correct and solves the problem. The approach is good, but could be more concise. For example, the helper function could be written as: def helper(nums, subset): subsets = [] for i in range(len(nums)): new_subset = subset + [nums[i]] subsets.append(new_subset) subsets += helper(nums[i+1:], new_subset) return subsets
Dec 10
Code Problem / Data Structures and Algorithms DifficultyMedium Python
This problem asks the programmer to return the sum of all integers at even indices in a given list. For example, given the list [1, 2, 3, 4, 5], the output would be 6 (2 + 4).
About this solution: This solution is correct and efficient. The candidate has demonstrated a good understanding of how to use the slice operator to get every other element in a list.
Dec 09
Code Problem / Data Structures and Algorithms DifficultyMedium C++
This function takes in a set of integers and a target value, and returns true if there is a pair of integers in the set that sum up to the target value. Otherwise, it returns false.
About this solution: The candidate's solution is complete and solves the problem. The approach is to use a hash map to store the complement of each number in the array. If the complement exists in the hash map, then a pair exists that sums up to the target value.
Dec 09
Code Problem / Data Structures and Algorithms DifficultyMedium Python
The function should return the sum of the integers that are hashed to odd values.
About this solution: The candidate's solution is optimal because it uses a generator expression to iterate over the list and sum only the values that hash to odd values. This is optimal because it is a single pass over the list and uses a generator expression to avoid creating a new list.
Dec 09
Supervised learning involves training a model on labeled data, so that it can learn to predict the correct labels for new data. Unsupervised learning involves training a model on unlabeled data , so that it can learn to find patterns in the data. Reinforcement learning involves training a model by providing it with feedback on its performance, so that it can learn to maximize its reward.
About this solution: The candidate's solution correctly explains the three types of machine learning. However, the candidate could provide more specific examples to illustrate each type of learning. For example, for supervised learning, the candidate could explain that a common type of supervised learning is classification, where the algorithm is given a set of labeled data (e.g. images of animals that are labeled as "cat" or "dog") and is then tasked with correctly labeling new data. For unsupervised learning, the candidate could explain that a common type of unsupervised learning is clustering, where the algorithm is given a set of data points and must group them into clusters based on similarity. For reinforcement learning, the candidate could explain that a common type of reinforcement learning is learning to play a video game, where the algorithm is given a reward for each step closer it gets to winning the game.
Dec 09
Code Problem / Data Structures and Algorithms DifficultyMedium Python
Given an array of n integers, this algorithm will find the maximum sum of any contiguous subarray of the array. For example, given the input array [1, -3, 2, 1, -1], the algorithm would output 3.
About this solution: The candidate's solution correctly finds the maximum sum of any contiguous subarray of the given array. The approach is to keep track of the current sum as we iterate through the array, and update the maximum sum if necessary. If the current sum ever becomes negative, we reset it to 0 since we know that a subarray with a negative sum will never be the maximum sum.
Dec 09
Code Problem / Data Structures and Algorithms DifficultyMedium C++
The problem asks for a way to determine whether there is a route between two nodes in a directed graph. One example is given, where the nodes are connected in a linear fashion. The solution should work for more general cases as well.
About this solution: The candidate's solution is complete and solves the problem. The candidate has used a breadth-first search approach, which is a good choice for this problem.
Dec 08