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[ { "from": "human", "value": "**Course Schedule II (Topological Sort)** (Hard)\n\nThere are `numCourses` courses labeled from 0 to numCourses-1. Given `prerequisites[i] = [a, b]` meaning you must take course b before course a, return the ordering of courses you should take to finish all courses. If impossibl...
{ "category": "graphs", "difficulty": "hard", "language": "python", "title": "Course Schedule II (Topological Sort)" }
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[ { "from": "human", "value": "**Group Anagrams** (Medium)\n\nGiven an array of strings `strs`, group the anagrams together. You can return the answer in any order.\n\nPlease provide a solution in python with a clear explanation of the approach, time/space complexity, and any important edge cases." }, { ...
{ "category": "arrays_hashing", "difficulty": "medium", "language": "python", "title": "Group Anagrams" }
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[ { "from": "human", "value": "How would you answer: 'Tell me about a significant technical mistake you made and what you learned from it.'" }, { "from": "gpt", "value": "**Strong Answer:**\n\n**The Mistake:**\nTwo years ago, I was deploying a database schema migration on a production PostgreSQL t...
{ "category": "behavioral", "difficulty": "medium", "language": "behavioral", "title": "Describe a Time You Made a Mistake" }
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[ { "from": "human", "value": "**Group Anagrams** (Medium)\n\nGiven an array of strings `strs`, group the anagrams together. You can return the answer in any order.\n\nPlease provide a solution in python with a clear explanation of the approach, time/space complexity, and any important edge cases." }, { ...
{ "category": "arrays_hashing", "difficulty": "medium", "language": "python", "title": "Group Anagrams" }
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[ { "from": "human", "value": "Design a rate limiter that can be used as middleware for a web API. Support multiple rate limiting strategies and work across distributed servers." }, { "from": "gpt", "value": "## System Design: Distributed Rate Limiter\n\n### Requirements\n- Limit requests per user...
{ "category": "system_design", "difficulty": "hard", "language": "conceptual", "title": "Design a Rate Limiter" }
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[ { "from": "human", "value": "How would you answer: 'Tell me about a significant technical mistake you made and what you learned from it.'" }, { "from": "gpt", "value": "**Strong Answer:**\n\n**The Mistake:**\nTwo years ago, I was deploying a database schema migration on a production PostgreSQL t...
{ "category": "behavioral", "difficulty": "medium", "language": "behavioral", "title": "Describe a Time You Made a Mistake" }
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[ { "from": "human", "value": "How would you answer: 'Tell me about a significant technical mistake you made and what you learned from it.'" }, { "from": "gpt", "value": "**Strong Answer:**\n\n**The Mistake:**\nTwo years ago, I was deploying a database schema migration on a production PostgreSQL t...
{ "category": "behavioral", "difficulty": "medium", "language": "behavioral", "title": "Describe a Time You Made a Mistake" }
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[ { "from": "human", "value": "**Container With Most Water** (Medium)\n\nGiven an integer array `height` of length n, where each element represents the height of a vertical line at position i. Find two lines that together with the x-axis form a container that holds the most water. Return the maximum amount of...
{ "category": "two_pointers", "difficulty": "medium", "language": "python", "title": "Container With Most Water" }
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[ { "from": "human", "value": "**Top K Frequent Elements** (Medium)\n\nGiven an integer array `nums` and an integer `k`, return the `k` most frequent elements. You may return the answer in any order.\n\nPlease provide a solution in python with a clear explanation of the approach, time/space complexity, and an...
{ "category": "heap_priority_queue", "difficulty": "medium", "language": "python", "title": "Top K Frequent Elements" }
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[ { "from": "human", "value": "**Binary Tree Level Order Traversal** (Medium)\n\nGiven the root of a binary tree, return the level order traversal of its nodes' values (i.e., from left to right, level by level).\n\nPlease provide a solution in python with a clear explanation of the approach, time/space comple...
{ "category": "trees", "difficulty": "medium", "language": "python", "title": "Binary Tree Level Order Traversal" }
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[ { "from": "human", "value": "**Number of Islands** (Medium)\n\nGiven an `m x n` 2D binary grid where '1' represents land and '0' represents water, return the number of islands. An island is surrounded by water and is formed by connecting adjacent lands horizontally or vertically.\n\nPlease provide a solutio...
{ "category": "graphs", "difficulty": "medium", "language": "python", "title": "Number of Islands" }
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[ { "from": "human", "value": "**Binary Tree Level Order Traversal** (Medium)\n\nGiven the root of a binary tree, return the level order traversal of its nodes' values (i.e., from left to right, level by level).\n\nPlease provide a solution in python with a clear explanation of the approach, time/space comple...
{ "category": "trees", "difficulty": "medium", "language": "python", "title": "Binary Tree Level Order Traversal" }
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[ { "from": "human", "value": "Design a URL shortening service like bit.ly. The system should support: creating short URLs from long URLs, redirecting short URLs to original URLs, and optionally tracking click analytics." }, { "from": "gpt", "value": "## System Design: URL Shortener\n\n### Require...
{ "category": "system_design", "difficulty": "hard", "language": "conceptual", "title": "Design a URL Shortener" }
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[ { "from": "human", "value": "**Container With Most Water** (Medium)\n\nGiven an integer array `height` of length n, where each element represents the height of a vertical line at position i. Find two lines that together with the x-axis form a container that holds the most water. Return the maximum amount of...
{ "category": "two_pointers", "difficulty": "medium", "language": "python", "title": "Container With Most Water" }
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[ { "from": "human", "value": "**Binary Tree Level Order Traversal** (Medium)\n\nGiven the root of a binary tree, return the level order traversal of its nodes' values (i.e., from left to right, level by level).\n\nPlease provide a solution in python with a clear explanation of the approach, time/space comple...
{ "category": "trees", "difficulty": "medium", "language": "python", "title": "Binary Tree Level Order Traversal" }
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[ { "from": "human", "value": "**Daily Temperatures** (Medium)\n\nGiven an array of integers `temperatures` representing daily temperatures, return an array `answer` such that `answer[i]` is the number of days you have to wait after the `i`-th day to get a warmer temperature. If there is no future day with a ...
{ "category": "stack_queue", "difficulty": "medium", "language": "python", "title": "Daily Temperatures" }
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[ { "from": "human", "value": "**Coin Change** (Medium)\n\nYou are given an integer array `coins` representing coins of different denominations and an integer `amount` representing a total amount of money. Return the fewest number of coins needed to make up that amount. If that amount of money cannot be made ...
{ "category": "dynamic_programming", "difficulty": "medium", "language": "python", "title": "Coin Change" }
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[ { "from": "human", "value": "**Number of Islands** (Medium)\n\nGiven an `m x n` 2D binary grid where '1' represents land and '0' represents water, return the number of islands. An island is surrounded by water and is formed by connecting adjacent lands horizontally or vertically.\n\nPlease provide a solutio...
{ "category": "graphs", "difficulty": "medium", "language": "python", "title": "Number of Islands" }
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[ { "from": "human", "value": "**Number of Islands** (Medium)\n\nGiven an `m x n` 2D binary grid where '1' represents land and '0' represents water, return the number of islands. An island is surrounded by water and is formed by connecting adjacent lands horizontally or vertically.\n\nPlease provide a solutio...
{ "category": "graphs", "difficulty": "medium", "language": "python", "title": "Number of Islands" }
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[ { "from": "human", "value": "**Container With Most Water** (Medium)\n\nGiven an integer array `height` of length n, where each element represents the height of a vertical line at position i. Find two lines that together with the x-axis form a container that holds the most water. Return the maximum amount of...
{ "category": "two_pointers", "difficulty": "medium", "language": "python", "title": "Container With Most Water" }
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[ { "from": "human", "value": "**Coin Change** (Medium)\n\nYou are given an integer array `coins` representing coins of different denominations and an integer `amount` representing a total amount of money. Return the fewest number of coins needed to make up that amount. If that amount of money cannot be made ...
{ "category": "dynamic_programming", "difficulty": "medium", "language": "python", "title": "Coin Change" }
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[ { "from": "human", "value": "**Course Schedule II (Topological Sort)** (Hard)\n\nThere are `numCourses` courses labeled from 0 to numCourses-1. Given `prerequisites[i] = [a, b]` meaning you must take course b before course a, return the ordering of courses you should take to finish all courses. If impossibl...
{ "category": "graphs", "difficulty": "hard", "language": "python", "title": "Course Schedule II (Topological Sort)" }
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[ { "from": "human", "value": "**Daily Temperatures** (Medium)\n\nGiven an array of integers `temperatures` representing daily temperatures, return an array `answer` such that `answer[i]` is the number of days you have to wait after the `i`-th day to get a warmer temperature. If there is no future day with a ...
{ "category": "stack_queue", "difficulty": "medium", "language": "python", "title": "Daily Temperatures" }
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[ { "from": "human", "value": "**Course Schedule II (Topological Sort)** (Hard)\n\nThere are `numCourses` courses labeled from 0 to numCourses-1. Given `prerequisites[i] = [a, b]` meaning you must take course b before course a, return the ordering of courses you should take to finish all courses. If impossibl...
{ "category": "graphs", "difficulty": "hard", "language": "python", "title": "Course Schedule II (Topological Sort)" }
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[ { "from": "human", "value": "**Top K Frequent Elements** (Medium)\n\nGiven an integer array `nums` and an integer `k`, return the `k` most frequent elements. You may return the answer in any order.\n\nPlease provide a solution in python with a clear explanation of the approach, time/space complexity, and an...
{ "category": "heap_priority_queue", "difficulty": "medium", "language": "python", "title": "Top K Frequent Elements" }
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[ { "from": "human", "value": "**Number of Islands** (Medium)\n\nGiven an `m x n` 2D binary grid where '1' represents land and '0' represents water, return the number of islands. An island is surrounded by water and is formed by connecting adjacent lands horizontally or vertically.\n\nPlease provide a solutio...
{ "category": "graphs", "difficulty": "medium", "language": "python", "title": "Number of Islands" }
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[ { "from": "human", "value": "**Reverse a Linked List** (Easy)\n\nGiven the head of a singly linked list, reverse the list and return the reversed list's head. Solve it both iteratively and recursively.\n\nPlease provide a solution in python with a clear explanation of the approach, time/space complexity, an...
{ "category": "linked_list", "difficulty": "easy", "language": "python", "title": "Reverse a Linked List" }
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[ { "from": "human", "value": "**Binary Tree Level Order Traversal** (Medium)\n\nGiven the root of a binary tree, return the level order traversal of its nodes' values (i.e., from left to right, level by level).\n\nPlease provide a solution in python with a clear explanation of the approach, time/space comple...
{ "category": "trees", "difficulty": "medium", "language": "python", "title": "Binary Tree Level Order Traversal" }
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[ { "from": "human", "value": "**Daily Temperatures** (Medium)\n\nGiven an array of integers `temperatures` representing daily temperatures, return an array `answer` such that `answer[i]` is the number of days you have to wait after the `i`-th day to get a warmer temperature. If there is no future day with a ...
{ "category": "stack_queue", "difficulty": "medium", "language": "python", "title": "Daily Temperatures" }
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[ { "from": "human", "value": "**Top K Frequent Elements** (Medium)\n\nGiven an integer array `nums` and an integer `k`, return the `k` most frequent elements. You may return the answer in any order.\n\nPlease provide a solution in python with a clear explanation of the approach, time/space complexity, and an...
{ "category": "heap_priority_queue", "difficulty": "medium", "language": "python", "title": "Top K Frequent Elements" }
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[ { "from": "human", "value": "**Reverse a Linked List** (Easy)\n\nGiven the head of a singly linked list, reverse the list and return the reversed list's head. Solve it both iteratively and recursively.\n\nPlease provide a solution in python with a clear explanation of the approach, time/space complexity, an...
{ "category": "linked_list", "difficulty": "easy", "language": "python", "title": "Reverse a Linked List" }
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[ { "from": "human", "value": "**Number of Islands** (Medium)\n\nGiven an `m x n` 2D binary grid where '1' represents land and '0' represents water, return the number of islands. An island is surrounded by water and is formed by connecting adjacent lands horizontally or vertically.\n\nPlease provide a solutio...
{ "category": "graphs", "difficulty": "medium", "language": "python", "title": "Number of Islands" }
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[ { "from": "human", "value": "**Top K Frequent Elements** (Medium)\n\nGiven an integer array `nums` and an integer `k`, return the `k` most frequent elements. You may return the answer in any order.\n\nPlease provide a solution in python with a clear explanation of the approach, time/space complexity, and an...
{ "category": "heap_priority_queue", "difficulty": "medium", "language": "python", "title": "Top K Frequent Elements" }
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[ { "from": "human", "value": "**Longest Substring Without Repeating Characters** (Medium)\n\nGiven a string `s`, find the length of the longest substring without repeating characters.\n\nPlease provide a solution in python with a clear explanation of the approach, time/space complexity, and any important edg...
{ "category": "sliding_window", "difficulty": "medium", "language": "python", "title": "Longest Substring Without Repeating Characters" }
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[ { "from": "human", "value": "**Binary Tree Level Order Traversal** (Medium)\n\nGiven the root of a binary tree, return the level order traversal of its nodes' values (i.e., from left to right, level by level).\n\nPlease provide a solution in python with a clear explanation of the approach, time/space comple...
{ "category": "trees", "difficulty": "medium", "language": "python", "title": "Binary Tree Level Order Traversal" }
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[ { "from": "human", "value": "**Top K Frequent Elements** (Medium)\n\nGiven an integer array `nums` and an integer `k`, return the `k` most frequent elements. You may return the answer in any order.\n\nPlease provide a solution in python with a clear explanation of the approach, time/space complexity, and an...
{ "category": "heap_priority_queue", "difficulty": "medium", "language": "python", "title": "Top K Frequent Elements" }
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[ { "from": "human", "value": "**Coin Change** (Medium)\n\nYou are given an integer array `coins` representing coins of different denominations and an integer `amount` representing a total amount of money. Return the fewest number of coins needed to make up that amount. If that amount of money cannot be made ...
{ "category": "dynamic_programming", "difficulty": "medium", "language": "python", "title": "Coin Change" }
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[ { "from": "human", "value": "**Longest Increasing Subsequence** (Hard)\n\nGiven an integer array `nums`, return the length of the longest strictly increasing subsequence.\n\nPlease provide a solution in python with a clear explanation of the approach, time/space complexity, and any important edge cases." ...
{ "category": "dynamic_programming", "difficulty": "hard", "language": "python", "title": "Longest Increasing Subsequence" }
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[ { "from": "human", "value": "**Reverse a Linked List** (Easy)\n\nGiven the head of a singly linked list, reverse the list and return the reversed list's head. Solve it both iteratively and recursively.\n\nPlease provide a solution in python with a clear explanation of the approach, time/space complexity, an...
{ "category": "linked_list", "difficulty": "easy", "language": "python", "title": "Reverse a Linked List" }
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[ { "from": "human", "value": "**Number of Islands** (Medium)\n\nGiven an `m x n` 2D binary grid where '1' represents land and '0' represents water, return the number of islands. An island is surrounded by water and is formed by connecting adjacent lands horizontally or vertically.\n\nPlease provide a solutio...
{ "category": "graphs", "difficulty": "medium", "language": "python", "title": "Number of Islands" }
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[ { "from": "human", "value": "How would you answer the behavioral interview question: 'Tell me about a time you disagreed with your manager or a technical decision, and how you handled it.'" }, { "from": "gpt", "value": "**Strong Answer (STAR Format):**\n\n**Situation:**\nAt my previous role, our...
{ "category": "behavioral", "difficulty": "medium", "language": "behavioral", "title": "Tell Me About a Time You Disagreed With Your Manager" }
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[ { "from": "human", "value": "**Daily Temperatures** (Medium)\n\nGiven an array of integers `temperatures` representing daily temperatures, return an array `answer` such that `answer[i]` is the number of days you have to wait after the `i`-th day to get a warmer temperature. If there is no future day with a ...
{ "category": "stack_queue", "difficulty": "medium", "language": "python", "title": "Daily Temperatures" }
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[ { "from": "human", "value": "**Edit Distance (Levenshtein Distance)** (Hard)\n\nGiven two strings `word1` and `word2`, return the minimum number of operations required to convert `word1` to `word2`. Operations allowed: insert a character, delete a character, replace a character.\n\nPlease provide a solution...
{ "category": "dynamic_programming", "difficulty": "hard", "language": "python", "title": "Edit Distance (Levenshtein Distance)" }
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[ { "from": "human", "value": "Design a URL shortening service like bit.ly. The system should support: creating short URLs from long URLs, redirecting short URLs to original URLs, and optionally tracking click analytics." }, { "from": "gpt", "value": "## System Design: URL Shortener\n\n### Require...
{ "category": "system_design", "difficulty": "hard", "language": "conceptual", "title": "Design a URL Shortener" }
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[ { "from": "human", "value": "**Subsets** (Medium)\n\nGiven an integer array `nums` of unique elements, return all possible subsets (the power set). The solution set must not contain duplicate subsets. Return the solution in any order.\n\nPlease provide a solution in python with a clear explanation of the ap...
{ "category": "backtracking", "difficulty": "medium", "language": "python", "title": "Subsets" }
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[ { "from": "human", "value": "**Group Anagrams** (Medium)\n\nGiven an array of strings `strs`, group the anagrams together. You can return the answer in any order.\n\nPlease provide a solution in python with a clear explanation of the approach, time/space complexity, and any important edge cases." }, { ...
{ "category": "arrays_hashing", "difficulty": "medium", "language": "python", "title": "Group Anagrams" }
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[ { "from": "human", "value": "Design a URL shortening service like bit.ly. The system should support: creating short URLs from long URLs, redirecting short URLs to original URLs, and optionally tracking click analytics." }, { "from": "gpt", "value": "## System Design: URL Shortener\n\n### Require...
{ "category": "system_design", "difficulty": "hard", "language": "conceptual", "title": "Design a URL Shortener" }
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[ { "from": "human", "value": "**Daily Temperatures** (Medium)\n\nGiven an array of integers `temperatures` representing daily temperatures, return an array `answer` such that `answer[i]` is the number of days you have to wait after the `i`-th day to get a warmer temperature. If there is no future day with a ...
{ "category": "stack_queue", "difficulty": "medium", "language": "python", "title": "Daily Temperatures" }
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[ { "from": "human", "value": "**Two Sum** (Easy)\n\nGiven an array of integers `nums` and an integer `target`, return the indices of the two numbers that add up to `target`. You may assume that each input would have exactly one solution, and you may not use the same element twice.\n\nPlease provide a solutio...
{ "category": "arrays_hashing", "difficulty": "easy", "language": "python", "title": "Two Sum" }
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[ { "from": "human", "value": "**Coin Change** (Medium)\n\nYou are given an integer array `coins` representing coins of different denominations and an integer `amount` representing a total amount of money. Return the fewest number of coins needed to make up that amount. If that amount of money cannot be made ...
{ "category": "dynamic_programming", "difficulty": "medium", "language": "python", "title": "Coin Change" }
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[ { "from": "human", "value": "How would you answer the behavioral interview question: 'Tell me about a time you disagreed with your manager or a technical decision, and how you handled it.'" }, { "from": "gpt", "value": "**Strong Answer (STAR Format):**\n\n**Situation:**\nAt my previous role, our...
{ "category": "behavioral", "difficulty": "medium", "language": "behavioral", "title": "Tell Me About a Time You Disagreed With Your Manager" }
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[ { "from": "human", "value": "**Longest Substring Without Repeating Characters** (Medium)\n\nGiven a string `s`, find the length of the longest substring without repeating characters.\n\nPlease provide a solution in python with a clear explanation of the approach, time/space complexity, and any important edg...
{ "category": "sliding_window", "difficulty": "medium", "language": "python", "title": "Longest Substring Without Repeating Characters" }
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[ { "from": "human", "value": "**Number of Islands** (Medium)\n\nGiven an `m x n` 2D binary grid where '1' represents land and '0' represents water, return the number of islands. An island is surrounded by water and is formed by connecting adjacent lands horizontally or vertically.\n\nPlease provide a solutio...
{ "category": "graphs", "difficulty": "medium", "language": "python", "title": "Number of Islands" }
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[ { "from": "human", "value": "**Top K Frequent Elements** (Medium)\n\nGiven an integer array `nums` and an integer `k`, return the `k` most frequent elements. You may return the answer in any order.\n\nPlease provide a solution in python with a clear explanation of the approach, time/space complexity, and an...
{ "category": "heap_priority_queue", "difficulty": "medium", "language": "python", "title": "Top K Frequent Elements" }
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[ { "from": "human", "value": "**Subsets** (Medium)\n\nGiven an integer array `nums` of unique elements, return all possible subsets (the power set). The solution set must not contain duplicate subsets. Return the solution in any order.\n\nPlease provide a solution in python with a clear explanation of the ap...
{ "category": "backtracking", "difficulty": "medium", "language": "python", "title": "Subsets" }
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[ { "from": "human", "value": "Design a scalable notification system that supports push notifications, email, and SMS. The system should handle millions of users and support different notification types with user preferences." }, { "from": "gpt", "value": "## System Design: Notification System\n\n...
{ "category": "system_design", "difficulty": "hard", "language": "conceptual", "title": "Design a Notification System" }
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[ { "from": "human", "value": "**Number of Islands** (Medium)\n\nGiven an `m x n` 2D binary grid where '1' represents land and '0' represents water, return the number of islands. An island is surrounded by water and is formed by connecting adjacent lands horizontally or vertically.\n\nPlease provide a solutio...
{ "category": "graphs", "difficulty": "medium", "language": "python", "title": "Number of Islands" }
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[ { "from": "human", "value": "**Top K Frequent Elements** (Medium)\n\nGiven an integer array `nums` and an integer `k`, return the `k` most frequent elements. You may return the answer in any order.\n\nPlease provide a solution in python with a clear explanation of the approach, time/space complexity, and an...
{ "category": "heap_priority_queue", "difficulty": "medium", "language": "python", "title": "Top K Frequent Elements" }
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[ { "from": "human", "value": "**Edit Distance (Levenshtein Distance)** (Hard)\n\nGiven two strings `word1` and `word2`, return the minimum number of operations required to convert `word1` to `word2`. Operations allowed: insert a character, delete a character, replace a character.\n\nPlease provide a solution...
{ "category": "dynamic_programming", "difficulty": "hard", "language": "python", "title": "Edit Distance (Levenshtein Distance)" }
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[ { "from": "human", "value": "**Top K Frequent Elements** (Medium)\n\nGiven an integer array `nums` and an integer `k`, return the `k` most frequent elements. You may return the answer in any order.\n\nPlease provide a solution in python with a clear explanation of the approach, time/space complexity, and an...
{ "category": "heap_priority_queue", "difficulty": "medium", "language": "python", "title": "Top K Frequent Elements" }
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[ { "from": "human", "value": "**Edit Distance (Levenshtein Distance)** (Hard)\n\nGiven two strings `word1` and `word2`, return the minimum number of operations required to convert `word1` to `word2`. Operations allowed: insert a character, delete a character, replace a character.\n\nPlease provide a solution...
{ "category": "dynamic_programming", "difficulty": "hard", "language": "python", "title": "Edit Distance (Levenshtein Distance)" }
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[ { "from": "human", "value": "**Group Anagrams** (Medium)\n\nGiven an array of strings `strs`, group the anagrams together. You can return the answer in any order.\n\nPlease provide a solution in python with a clear explanation of the approach, time/space complexity, and any important edge cases." }, { ...
{ "category": "arrays_hashing", "difficulty": "medium", "language": "python", "title": "Group Anagrams" }
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[ { "from": "human", "value": "Design a scalable notification system that supports push notifications, email, and SMS. The system should handle millions of users and support different notification types with user preferences." }, { "from": "gpt", "value": "## System Design: Notification System\n\n...
{ "category": "system_design", "difficulty": "hard", "language": "conceptual", "title": "Design a Notification System" }
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[ { "from": "human", "value": "**Daily Temperatures** (Medium)\n\nGiven an array of integers `temperatures` representing daily temperatures, return an array `answer` such that `answer[i]` is the number of days you have to wait after the `i`-th day to get a warmer temperature. If there is no future day with a ...
{ "category": "stack_queue", "difficulty": "medium", "language": "python", "title": "Daily Temperatures" }
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[ { "from": "human", "value": "**Container With Most Water** (Medium)\n\nGiven an integer array `height` of length n, where each element represents the height of a vertical line at position i. Find two lines that together with the x-axis form a container that holds the most water. Return the maximum amount of...
{ "category": "two_pointers", "difficulty": "medium", "language": "python", "title": "Container With Most Water" }
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[ { "from": "human", "value": "**Group Anagrams** (Medium)\n\nGiven an array of strings `strs`, group the anagrams together. You can return the answer in any order.\n\nPlease provide a solution in python with a clear explanation of the approach, time/space complexity, and any important edge cases." }, { ...
{ "category": "arrays_hashing", "difficulty": "medium", "language": "python", "title": "Group Anagrams" }
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[ { "from": "human", "value": "**Group Anagrams** (Medium)\n\nGiven an array of strings `strs`, group the anagrams together. You can return the answer in any order.\n\nPlease provide a solution in python with a clear explanation of the approach, time/space complexity, and any important edge cases." }, { ...
{ "category": "arrays_hashing", "difficulty": "medium", "language": "python", "title": "Group Anagrams" }
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[ { "from": "human", "value": "Design a rate limiter that can be used as middleware for a web API. Support multiple rate limiting strategies and work across distributed servers." }, { "from": "gpt", "value": "## System Design: Distributed Rate Limiter\n\n### Requirements\n- Limit requests per user...
{ "category": "system_design", "difficulty": "hard", "language": "conceptual", "title": "Design a Rate Limiter" }
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[ { "from": "human", "value": "**Container With Most Water** (Medium)\n\nGiven an integer array `height` of length n, where each element represents the height of a vertical line at position i. Find two lines that together with the x-axis form a container that holds the most water. Return the maximum amount of...
{ "category": "two_pointers", "difficulty": "medium", "language": "python", "title": "Container With Most Water" }
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[ { "from": "human", "value": "**Course Schedule II (Topological Sort)** (Hard)\n\nThere are `numCourses` courses labeled from 0 to numCourses-1. Given `prerequisites[i] = [a, b]` meaning you must take course b before course a, return the ordering of courses you should take to finish all courses. If impossibl...
{ "category": "graphs", "difficulty": "hard", "language": "python", "title": "Course Schedule II (Topological Sort)" }
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[ { "from": "human", "value": "**Number of Islands** (Medium)\n\nGiven an `m x n` 2D binary grid where '1' represents land and '0' represents water, return the number of islands. An island is surrounded by water and is formed by connecting adjacent lands horizontally or vertically.\n\nPlease provide a solutio...
{ "category": "graphs", "difficulty": "medium", "language": "python", "title": "Number of Islands" }
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[ { "from": "human", "value": "**Longest Substring Without Repeating Characters** (Medium)\n\nGiven a string `s`, find the length of the longest substring without repeating characters.\n\nPlease provide a solution in python with a clear explanation of the approach, time/space complexity, and any important edg...
{ "category": "sliding_window", "difficulty": "medium", "language": "python", "title": "Longest Substring Without Repeating Characters" }
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[ { "from": "human", "value": "**Binary Tree Level Order Traversal** (Medium)\n\nGiven the root of a binary tree, return the level order traversal of its nodes' values (i.e., from left to right, level by level).\n\nPlease provide a solution in python with a clear explanation of the approach, time/space comple...
{ "category": "trees", "difficulty": "medium", "language": "python", "title": "Binary Tree Level Order Traversal" }
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[ { "from": "human", "value": "**Reverse a Linked List** (Easy)\n\nGiven the head of a singly linked list, reverse the list and return the reversed list's head. Solve it both iteratively and recursively.\n\nPlease provide a solution in python with a clear explanation of the approach, time/space complexity, an...
{ "category": "linked_list", "difficulty": "easy", "language": "python", "title": "Reverse a Linked List" }
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[ { "from": "human", "value": "**Longest Increasing Subsequence** (Hard)\n\nGiven an integer array `nums`, return the length of the longest strictly increasing subsequence.\n\nPlease provide a solution in python with a clear explanation of the approach, time/space complexity, and any important edge cases." ...
{ "category": "dynamic_programming", "difficulty": "hard", "language": "python", "title": "Longest Increasing Subsequence" }
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[ { "from": "human", "value": "**Number of Islands** (Medium)\n\nGiven an `m x n` 2D binary grid where '1' represents land and '0' represents water, return the number of islands. An island is surrounded by water and is formed by connecting adjacent lands horizontally or vertically.\n\nPlease provide a solutio...
{ "category": "graphs", "difficulty": "medium", "language": "python", "title": "Number of Islands" }
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[ { "from": "human", "value": "How would you answer: 'Tell me about a significant technical mistake you made and what you learned from it.'" }, { "from": "gpt", "value": "**Strong Answer:**\n\n**The Mistake:**\nTwo years ago, I was deploying a database schema migration on a production PostgreSQL t...
{ "category": "behavioral", "difficulty": "medium", "language": "behavioral", "title": "Describe a Time You Made a Mistake" }
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[ { "from": "human", "value": "**Group Anagrams** (Medium)\n\nGiven an array of strings `strs`, group the anagrams together. You can return the answer in any order.\n\nPlease provide a solution in python with a clear explanation of the approach, time/space complexity, and any important edge cases." }, { ...
{ "category": "arrays_hashing", "difficulty": "medium", "language": "python", "title": "Group Anagrams" }
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[ { "from": "human", "value": "**Container With Most Water** (Medium)\n\nGiven an integer array `height` of length n, where each element represents the height of a vertical line at position i. Find two lines that together with the x-axis form a container that holds the most water. Return the maximum amount of...
{ "category": "two_pointers", "difficulty": "medium", "language": "python", "title": "Container With Most Water" }
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[ { "from": "human", "value": "**Two Sum** (Easy)\n\nGiven an array of integers `nums` and an integer `target`, return the indices of the two numbers that add up to `target`. You may assume that each input would have exactly one solution, and you may not use the same element twice.\n\nPlease provide a solutio...
{ "category": "arrays_hashing", "difficulty": "easy", "language": "python", "title": "Two Sum" }
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[ { "from": "human", "value": "**Daily Temperatures** (Medium)\n\nGiven an array of integers `temperatures` representing daily temperatures, return an array `answer` such that `answer[i]` is the number of days you have to wait after the `i`-th day to get a warmer temperature. If there is no future day with a ...
{ "category": "stack_queue", "difficulty": "medium", "language": "python", "title": "Daily Temperatures" }
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[ { "from": "human", "value": "**Top K Frequent Elements** (Medium)\n\nGiven an integer array `nums` and an integer `k`, return the `k` most frequent elements. You may return the answer in any order.\n\nPlease provide a solution in python with a clear explanation of the approach, time/space complexity, and an...
{ "category": "heap_priority_queue", "difficulty": "medium", "language": "python", "title": "Top K Frequent Elements" }
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[ { "from": "human", "value": "**Binary Tree Level Order Traversal** (Medium)\n\nGiven the root of a binary tree, return the level order traversal of its nodes' values (i.e., from left to right, level by level).\n\nPlease provide a solution in python with a clear explanation of the approach, time/space comple...
{ "category": "trees", "difficulty": "medium", "language": "python", "title": "Binary Tree Level Order Traversal" }
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[ { "from": "human", "value": "How would you answer: 'Tell me about a significant technical mistake you made and what you learned from it.'" }, { "from": "gpt", "value": "**Strong Answer:**\n\n**The Mistake:**\nTwo years ago, I was deploying a database schema migration on a production PostgreSQL t...
{ "category": "behavioral", "difficulty": "medium", "language": "behavioral", "title": "Describe a Time You Made a Mistake" }
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[ { "from": "human", "value": "How would you answer the behavioral interview question: 'Tell me about a time you disagreed with your manager or a technical decision, and how you handled it.'" }, { "from": "gpt", "value": "**Strong Answer (STAR Format):**\n\n**Situation:**\nAt my previous role, our...
{ "category": "behavioral", "difficulty": "medium", "language": "behavioral", "title": "Tell Me About a Time You Disagreed With Your Manager" }
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[ { "from": "human", "value": "**Two Sum** (Easy)\n\nGiven an array of integers `nums` and an integer `target`, return the indices of the two numbers that add up to `target`. You may assume that each input would have exactly one solution, and you may not use the same element twice.\n\nPlease provide a solutio...
{ "category": "arrays_hashing", "difficulty": "easy", "language": "python", "title": "Two Sum" }
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[ { "from": "human", "value": "**Longest Increasing Subsequence** (Hard)\n\nGiven an integer array `nums`, return the length of the longest strictly increasing subsequence.\n\nPlease provide a solution in python with a clear explanation of the approach, time/space complexity, and any important edge cases." ...
{ "category": "dynamic_programming", "difficulty": "hard", "language": "python", "title": "Longest Increasing Subsequence" }
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[ { "from": "human", "value": "How would you answer: 'Tell me about a significant technical mistake you made and what you learned from it.'" }, { "from": "gpt", "value": "**Strong Answer:**\n\n**The Mistake:**\nTwo years ago, I was deploying a database schema migration on a production PostgreSQL t...
{ "category": "behavioral", "difficulty": "medium", "language": "behavioral", "title": "Describe a Time You Made a Mistake" }
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[ { "from": "human", "value": "**Group Anagrams** (Medium)\n\nGiven an array of strings `strs`, group the anagrams together. You can return the answer in any order.\n\nPlease provide a solution in python with a clear explanation of the approach, time/space complexity, and any important edge cases." }, { ...
{ "category": "arrays_hashing", "difficulty": "medium", "language": "python", "title": "Group Anagrams" }
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[ { "from": "human", "value": "**Coin Change** (Medium)\n\nYou are given an integer array `coins` representing coins of different denominations and an integer `amount` representing a total amount of money. Return the fewest number of coins needed to make up that amount. If that amount of money cannot be made ...
{ "category": "dynamic_programming", "difficulty": "medium", "language": "python", "title": "Coin Change" }
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[ { "from": "human", "value": "How would you answer: 'Tell me about a significant technical mistake you made and what you learned from it.'" }, { "from": "gpt", "value": "**Strong Answer:**\n\n**The Mistake:**\nTwo years ago, I was deploying a database schema migration on a production PostgreSQL t...
{ "category": "behavioral", "difficulty": "medium", "language": "behavioral", "title": "Describe a Time You Made a Mistake" }
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[ { "from": "human", "value": "**Daily Temperatures** (Medium)\n\nGiven an array of integers `temperatures` representing daily temperatures, return an array `answer` such that `answer[i]` is the number of days you have to wait after the `i`-th day to get a warmer temperature. If there is no future day with a ...
{ "category": "stack_queue", "difficulty": "medium", "language": "python", "title": "Daily Temperatures" }
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[ { "from": "human", "value": "**Coin Change** (Medium)\n\nYou are given an integer array `coins` representing coins of different denominations and an integer `amount` representing a total amount of money. Return the fewest number of coins needed to make up that amount. If that amount of money cannot be made ...
{ "category": "dynamic_programming", "difficulty": "medium", "language": "python", "title": "Coin Change" }
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[ { "from": "human", "value": "**Binary Tree Level Order Traversal** (Medium)\n\nGiven the root of a binary tree, return the level order traversal of its nodes' values (i.e., from left to right, level by level).\n\nPlease provide a solution in python with a clear explanation of the approach, time/space comple...
{ "category": "trees", "difficulty": "medium", "language": "python", "title": "Binary Tree Level Order Traversal" }
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[ { "from": "human", "value": "Design a scalable notification system that supports push notifications, email, and SMS. The system should handle millions of users and support different notification types with user preferences." }, { "from": "gpt", "value": "## System Design: Notification System\n\n...
{ "category": "system_design", "difficulty": "hard", "language": "conceptual", "title": "Design a Notification System" }
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[ { "from": "human", "value": "**Coin Change** (Medium)\n\nYou are given an integer array `coins` representing coins of different denominations and an integer `amount` representing a total amount of money. Return the fewest number of coins needed to make up that amount. If that amount of money cannot be made ...
{ "category": "dynamic_programming", "difficulty": "medium", "language": "python", "title": "Coin Change" }
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[ { "from": "human", "value": "**Two Sum** (Easy)\n\nGiven an array of integers `nums` and an integer `target`, return the indices of the two numbers that add up to `target`. You may assume that each input would have exactly one solution, and you may not use the same element twice.\n\nPlease provide a solutio...
{ "category": "arrays_hashing", "difficulty": "easy", "language": "python", "title": "Two Sum" }
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[ { "from": "human", "value": "**Binary Tree Level Order Traversal** (Medium)\n\nGiven the root of a binary tree, return the level order traversal of its nodes' values (i.e., from left to right, level by level).\n\nPlease provide a solution in python with a clear explanation of the approach, time/space comple...
{ "category": "trees", "difficulty": "medium", "language": "python", "title": "Binary Tree Level Order Traversal" }
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[ { "from": "human", "value": "**Reverse a Linked List** (Easy)\n\nGiven the head of a singly linked list, reverse the list and return the reversed list's head. Solve it both iteratively and recursively.\n\nPlease provide a solution in python with a clear explanation of the approach, time/space complexity, an...
{ "category": "linked_list", "difficulty": "easy", "language": "python", "title": "Reverse a Linked List" }
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[ { "from": "human", "value": "**Container With Most Water** (Medium)\n\nGiven an integer array `height` of length n, where each element represents the height of a vertical line at position i. Find two lines that together with the x-axis form a container that holds the most water. Return the maximum amount of...
{ "category": "two_pointers", "difficulty": "medium", "language": "python", "title": "Container With Most Water" }
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