Code Problem
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Code Problem / Data Structures and Algorithms / Recursion (32)
Code Problem / Data Structures and Algorithms / Binary Search (30)
Code Problem / Data Structures and Algorithms / Linked Lists (26)
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Code Problem / Data Structures and Algorithms / Stacks and Queues (25)
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Code Problem / Data Structures and Algorithms / Arrays and Strings (19)
Databases / SQL / Database Normalization (18)
Code Problem / Data Structures and Algorithms / Time Complexity (17)
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This problem is about finding the largest integer in a list. An example input would be [1, 2, 3, 4, 5], and the expected output would be 5.
About this solution: This solution correctly returns the largest integer in the list. However, it is not very robust - for example, if the list is empty, it will return an error. A more robust solution would check for an empty list and return a suitable default value (e.g. 0).
Given an array of integers, the "Two Sum" problem is to find the indices of two numbers in the array that add up to a given target. There is always a unique solution to this problem.
About this solution: The candidate's solution is correct and demonstrates a level of completeness. The solution uses a dictionary to store the values of the array and uses the dictionary to check if the complement of the current value is in the dictionary. If it is, then the indices of the complement and the current value are returned. The time complexity of this solution is O(n) because the dictionary is iterated through once. The space complexity of this solution is O(n) because the dictionary is the same size as the array.
This problem asks whether a given list of integers contains a pair of numbers whose sum equals a given target value. For example, if the list is [1, 2, 3, 4, 5] and the target value is 6, the answer would be True (1 + 5 = 6).
About this solution: This is a great solution! The candidate has thought through the problem and come up with an optimal solution.
This technical problem asks you to implement a queue using two stacks. This can be done by pushing the elements onto one stack, and then popping them off onto the other stack when you need to dequeue an element.
About this solution: The candidate's solution correctly implements a queue using two stacks. The enqueue stack is used to push elements into the queue, and the dequeue stack is used to pop elements from the queue. The dequeue stack is only used when it is empty. When the dequeue stack is empty, the candidate correctly pops all the elements from the enqueue stack and pushes them into the dequeue stack. This way, the dequeue stack will always have the elements in the reverse order of the enqueue stack. This way, the first element pushed into the enqueue stack will be the first element to be popped from the dequeue stack. This way, the last element pushed into the enqueue stack will be the last element to be popped from the dequeue stack. In this way, the queue is correctly implemented using two stacks.
This is a backtracking problem where the goal is to find the longest path of consecutive integers in a 2D array, starting from the top left corner. The path can only move up, down, left, or right, and each cell can only be visited once.
About this solution: The candidate's solution is a depth first search algorithm that starts at the top left corner of the array and searches for the longest path. If the algorithm finds a path that is longer than the current longest path, it will update the longest path. The algorithm will continue to search for the longest path until it has visited every cell in the array. The algorithm will then return the longest path.
The solution is complete and solves the problem. The approach is general and could be applied to other problems.
This problem can be solved using a hashing approach. We can iterate through the array, adding each element to a hash table. Then, for each element, we can check if there is another element in the array that adds up to the target number. If so, we return the indices of the two numbers.
About this solution: This is a great solution! The candidate has thought about the problem and come up with a solution that is both complete and efficient. The candidate has also taken the time to explain the thought process behind the solution.
Given an array of integers and a value k, print all pairs that sum to k.
About this solution: The candidate's solution is correct and demonstrates a level of completeness. The approach is sound and the candidate has correctly identified the time and space complexity of the solution.
This problem asks you to find the sum of all the elements in an array, using recursion. That is, you need to define a function that takes in an array of integers, and returns the sum of all the integers in the array. For example, given the input [1, 2, 3, 4], your function should return 10.
About this solution: This solution is complete and solves the problem. The approach is straightforward and easy to follow.