Skip to main content
Practice

Coding Quiz

In this coding quiz, you will implement a custom hash table and use it to perform specific tasks in a program.

The hash table you need to implement should store key-value pairs and provide functionality to retrieve values for given keys.

In this problem, you will use the hash table to create a program that calculates the number of occurrences of each character in a given string.

Hash Table Code Template
class HashTable:
   def __init__(self):
      self.size = 256
      self.table = [[] for _ in range(self.size)]

   def put(self, key, value):
      hash_key = hash(key) % self.size

      for item in self.table[hash_key]:
         if item[0] == key:
            item[1] = value
            return

      self.table[hash_key].append([key, value])

   def get(self, key):
      hash_key = hash(key) % self.size

      for item in self.table[hash_key]:
         if item[0] == key:
            return item[1]

      return None

   def count_characters(self, string):
      # Write your code here
      return # Write your code here

def solution(s):
   hash_table = HashTable()
   return hash_table.count_characters(s)

Constraints​

  • The size of the hash table is fixed and set to 256.

Example Input/Output​

  • Input: "hello"

  • Output: {'h': 1, 'e': 1, 'l': 2, 'o': 1}

Want to learn more?

Join CodeFriends Plus membership or enroll in a course to start your journey.