The candidate is asked to write a python code uses a hash table to efficiently find the indices of two numbers in an array that add up to a given target value.
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Coding Test
20 mins
Beginner
1
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The code iterates through the array and checks if the complement of the current number (i.e. the difference between the target and the current number) exists in the hash table. If it does, it returns the indices of the two numbers. If not, it adds the current number and its index to the hash table. If no pair of numbers is found, it returns an empty list. This solution has a time complexity of O(n) and uses O(n) extra space.
Hashing is a technique used in the Two Sum problem to efficiently store and retrieve key-value pairs. In this context, hashing allows us to quickly check if a desired sum can be achieved by looking up the complement of each element in the hash table. By using a hash function to map keys to indexes, we can reduce the time complexity of searching for elements from O(n) to O(1). This makes the algorithm more efficient and is essential for solving the Two Sum problem in linear time.
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