Topic: hashing-problem / Level: beginner

• 1. Implement a function to count the frequency of each character in a string using a hash table.
• 2. Given an array of integers, write a program to find all pairs that sum to a specific target using a hash map.
• 3. Write a program to check if two strings are anagrams of each other using hashing.
• 4. Create a function that takes an array of integers and returns the first non-repeating integer.
• 5. Write a program to find the number of distinct elements in an array using a hash set.
• 6. Given a string, write a function to check if it contains all unique characters using a hash set.
• 7. Implement a function that returns the longest substring without repeating characters using hashing.
• 8. Write a program to find the intersection of two arrays using a hash map.
• 9. Create a function that checks if a given string is a palindrome using a hash map.
• 10. Write a program to group anagrams from a list of strings using a hash table.
• 11. Given a list of integers, find the maximum element using a hash map to track the counts.
• 12. Implement a function to find the number of times a given integer appears in an array using hashing.
• 13. Create a program that counts the vowels in a given string using a hash table.
• 14. Write a function that checks if a given array contains duplicate elements using a hash set.
• 15. Given two strings, implement a function to check if one string is a rotation of the other using hashing.
• 16. Write a program to determine if two arrays have any elements in common using a hash set.
• 17. Create a function that finds all elements that appear more than once in an array using a hash map.
• 18. Implement a function to find the minimum element in an array using a hash map for tracking indices.
• 19. Write a program to return the first repeated character in a string using a hash table.
• 20. Create a function that checks if all characters in a string are unique using a hash set.
• 21. Given a list of integers, write a function to find the second largest number using hashing.
• 22. Implement a program to count the number of words in a sentence using a hash map.
• 23. Create a function that returns the frequency of each word in a paragraph using hashing.
• 24. Write a program to check if a given string has balanced parentheses using a hash map.
• 25. Given two arrays, implement a function to find their symmetric difference using hashing.
• 26. Create a function that checks if an array is a subset of another using a hash set.
• 27. Write a program to find the longest repeating character in a string using hashing.
• 28. Implement a function that finds the unique characters in a string using a hash set.
• 29. Create a program to return the characters that appear in only one of two strings using hashing.
• 30. Given a string, write a function to find all permutations of the characters using hashing.
• 31. Write a program to check if a string can be formed by rearranging another string using hashing.
• 32. Create a function that finds the longest prefix which is also a suffix in a string using a hash table.
• 33. Implement a program to find the number of unique words in a book using a hash map.
• 34. Write a function to check if the frequency of characters in two strings is the same using hashing.
• 35. Create a function that returns the common characters in two strings using a hash set.
• 36. Given a list of integers, write a function to count the number of odd and even numbers using a hash map.
• 37. Implement a program that finds the frequency of each digit in a number using hashing.
• 38. Create a function to find the length of the longest substring with the same character using hashing.
• 39. Write a program to check if a string is a valid anagram of a palindrome using hashing.
• 40. Given a string, implement a function to find the longest substring that contains at most one repeating character using hashing.
• 41. Create a function that returns the indices of the first two numbers in an array that add up to a target using a hash map.
• 42. Write a program to find the number of palindromic substrings in a given string using hashing.
• 43. Implement a function to check if a string contains all the digits using a hash set.
• 44. Create a program that finds the longest substring that is a palindrome using hashing.
• 45. Given two strings, write a function to determine if they are isomorphic using hashing.
• 46. Write a program to find the maximum frequency of any character in a string using a hash map.
• 47. Create a function that counts the number of trailing zeros in a number using hashing.
• 48. Implement a program to find the frequency of each letter in the English alphabet in a given string using hashing.
• 49. Write a function to determine if two strings are mirror images of each other using hashing.
• 50. Create a function that checks if a string is a valid password (contains uppercase, lowercase, digits, and special characters) using hashing.

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