Topic: hashing-problem / Level: beginner

• 101. Implement a function to find the minimum number of unique characters in a string using hashing.
• 102. Write a program to check if a string can be formed from another string by adding characters using hashing.
• 103. Create a function to determine if a string is a valid number using hashing.
• 104. Given two strings, write a function to find the number of characters that need to be changed to make them equal using hashing.
• 105. Write a program to count the total number of spaces in a string using hashing.
• 106. Create a function that checks if two strings have the same character frequency using hashing.
• 107. Implement a function to find the first non-repeating integer in an array using a hash map.
• 108. Write a program to find the frequency of each unique word in a book using hashing.
• 109. Create a function that returns the character with the maximum frequency in a string using a hash map.
• 110. Given a list of words, write a program to determine if any two words are anagrams using hashing.
• 111. Write a function to find the minimum length of a substring that contains all unique characters using hashing.
• 112. Create a program that checks if an array can be sorted by swapping two elements using hashing.
• 113. Implement a function to count the total number of lowercase letters in a string using hashing.
• 114. Write a program to find the maximum length of a contiguous subarray with distinct characters using hashing.
• 115. Create a function that checks if a string contains all the alphabets using hashing.
• 116. Given a string, write a function to find the longest substring that is a palindrome using hashing.
• 117. Write a program to count the number of times a character appears in a string using a hash table.
• 118. Create a function that returns the first character that does not repeat in a string using hashing.
• 119. Implement a function to check if two strings are composed of the same characters using hashing.
• 120. Write a program to find the number of distinct integers in an array using a hash set.
• 121. Create a function that checks if a string contains balanced brackets using a hash map.
• 122. Given a list of integers, write a program to determine if any two numbers can form a specific sum using hashing.
• 123. Write a function to count the number of uppercase letters in a string using hashing.
• 124. Create a program that finds the common elements between two arrays using a hash map.
• 125. Implement a function to check if a string is a valid URL using hashing.
• 126. Write a program to find the maximum frequency of any word in a text using hashing.
• 127. Create a function that checks if a string contains valid parentheses using a hash map.
• 128. Given a string, write a function to count the occurrences of each vowel using a hash map.
• 129. Write a program to determine if two strings can be formed from the same characters using hashing.
• 130. Create a function that returns the character with the minimum frequency in a string using a hash table.
• 131. Implement a function to find the longest substring of consecutive characters in a string using hashing.
• 132. Write a program to count the number of unique words in a sentence using hashing.
• 133. Create a function that checks if an array is a subset of another using hashing.
• 134. Given a string, write a function to find the longest substring that contains at most two distinct characters using hashing.
• 135. Write a program to find the total number of characters in a string excluding spaces using a hash set.
• 136. Create a function that checks if a string can be rearranged to form a palindrome using hashing.
• 137. Implement a function to count the number of valid email addresses in a list using hashing.
• 138. Write a program to find the first duplicate character in a string using hashing.
• 139. Create a function that checks if a given string is a valid number using a hash map.
• 140. Given an array, write a program to return the indices of all occurrences of a target integer using hashing.
• 141. Write a function to find the maximum sum of any contiguous subarray using hashing.
• 142. Create a program that counts the number of distinct words in a paragraph using hashing.
• 143. Implement a function to check if two strings are permutations of each other using hashing.
• 144. Write a program to find the total number of consonants in a string using hashing.
• 145. Create a function that returns the first character that does not appear in another string using hashing.
• 146. Given a list of words, write a program to find all anagrams of a given word using hashing.
• 147. Write a function to find the total number of digits in a string using hashing.
• 148. Create a program that checks if a string can be formed from the characters of another string using hashing.
• 149. Implement a function to count the frequency of each digit in a number using hashing.
• 150. Write a program to find the maximum length of a substring that contains only unique characters using hashing.

• More Levels

• Intermediate
• Advanced