Topic: Hashing-question / Level: Beginner

• 151. Write a program to find the longest substring with at least k distinct characters using hashing.
• 152. Implement a function to check if a string contains valid parentheses using a hash map.
• 153. Create a hash map to track the number of comments on different blog posts.
• 154. Write a program to find the elements that occur more than once in an array using hashing.
• 155. Implement a function to check if a string is a valid anagram of a palindrome using hashing.
• 156. Create a hash table to store the ISBN numbers of books and their availability.
• 157. Write a program to find the total number of unique characters in a string using hashing.
• 158. Implement a function to find the longest substring that contains at most three distinct characters using hashing.
• 159. Create a hash set to keep track of visited cities in a travel itinerary.
• 160. Write a program to count the number of unique pairs in an array that sum to a target value using hashing.
• 161. Implement a function to check if two strings are anagrams using sorting and hashing.
• 162. Create a hash table to store employee IDs and their corresponding salaries.
• 163. Write a program to find the longest substring with an equal number of 0s and 1s using hashing.
• 164. Implement a function to find the first unique element in an array using hashing.
• 165. Create a hash map to track the number of shares for different social media posts.
• 166. Write a program to find the maximum length of a contiguous subarray with at most two distinct elements using hashing.
• 167. Implement a function to check if a string is a valid shuffle of two other strings using hashing.
• 168. Create a hash table to store student IDs and their corresponding GPAs.
• 169. Write a program to find the smallest substring containing all characters of a given string using hashing.
• 170. Implement a function to count the number of distinct substrings in a string using hashing.
• 171. Create a hash map to track the number of clicks on different links in a document.
• 172. Write a program to find the longest substring that contains the same character repeated at least k times using hashing.
• 173. Implement a function to find all unique words in a sentence using hashing.
• 174. Create a hash table to store product names and their corresponding prices.
• 175. Write a program to find the longest sequence of consecutive numbers in an array using hashing.
• 176. Implement a function to check if a string can be formed by concatenating substrings of another string using hashing.
• 177. Create a hash map to track the number of orders placed by different customers.
• 178. Write a program to find the maximum frequency of any character in a string using hashing.
• 179. Implement a function to find all pairs in an array that sum to a target using hashing.
• 180. Create a hash table to store song titles and their corresponding artists.

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