Here are several LeetCode problems for each dictionary concept:

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1. Do I need to map or associate data?

Mapping names to ages, words to definitions, or similar key-value relationships.

• Two Sum (Easy)
  Use a dictionary to map numbers to their indices to find two numbers that add up to a target.
• Roman to Integer (Easy)
  Map Roman numerals to their integer values for conversion.
• Isomorphic Strings (Easy)
  Use two dictionaries to map characters in one string to another and vice versa.
• Word Pattern (Easy)
  Map pattern characters to words and ensure the mapping is consistent.
• Design Underground System (Medium)
  Use dictionaries to map check-in and check-out data for computing average travel times.

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2. Will I frequently look up values by a unique key?

Retrieving a user's profile by username or similar operations.

• Two Sum (Easy)
  Store numbers in a dictionary to enable quick lookups for complements.
• Contains Duplicate II (Easy)
  Use a dictionary to check if the same value exists within a certain index range.
• Group Anagrams (Medium)
  Use a dictionary to group words that are anagrams of each other.
• Four Sum II (Medium)
  Use a dictionary to store sums of pairs from two arrays for quick lookup with sums of pairs from other arrays.
• Subarray Sum Equals K (Medium)
  Use a dictionary to store cumulative sums and their frequencies for quick lookup.

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3. Do I need to count, group, or aggregate data?

Counting word frequencies in a text or similar aggregations.

• Majority Element (Easy)
  Use a dictionary to count occurrences of elements and identify the majority.
• Top K Frequent Elements (Medium)
  Count the frequencies of elements and retrieve the top K frequent ones.
• Valid Anagram (Easy)
  Count character frequencies in both strings and compare.
• Minimum Index Sum of Two Lists (Easy)
  Use a dictionary to aggregate indices and find the restaurant with the lowest index sum.
• Count Good Meals (Medium)
  Count how many pairs of elements form powers of two using a dictionary.

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4. Does the data grow or change dynamically?

Adding or removing key-value pairs dynamically.

• Design a HashMap (Medium)
  Implement a dynamic hash map with support for add, remove, and get operations.
• LRU Cache (Medium)
  Use a dictionary to dynamically store key-value pairs with access time tracking.
• Insert Delete GetRandom O(1) (Medium)
  Use a dictionary to insert and remove elements dynamically in constant time.
• Design Twitter (Medium)
  Maintain dynamically changing data for user tweets and followers.
• Time-Based Key-Value Store (Medium)
  Use a dictionary of dictionaries to store and retrieve values dynamically based on timestamps.

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These problems provide a comprehensive set of challenges to strengthen your understanding of how to apply dictionaries in different scenarios!