Coding Challenge

Intervals are a common topic in algorithmic problems. In this post, we’ll tackle five key interval problems: Insert Interval, Merge Intervals, Non Overlapping Intervals, Meeting Rooms, and Meeting Rooms II. Each problem will be solved with code examples and explanations. 1. Insert Interval Problem: Given a set of non-overlapping intervals sorted by their start time, insert a new interval into the intervals (merge if necessary) and return the result. Code Solution (Java):...

Category Problem Key Concepts/Strategies Detailed Explanation Code Example Arrays & Hashing Contains Duplicate Use a set to track seen numbers Iterate through the array, adding each element to the set; return true if an element is already in the set. Valid Anagram Use a hashmap to count character frequencies Count characters in both strings using hashmaps and compare the counts. Two Sum Use a hashmap to store indices of elements Iterate through the array, for each element, check if the complement (target - element) exists in the hashmap....

Question: Given an array of strings strs, group the anagrams together. Answer: To group anagrams together, you can use a dictionary to map sorted strings to their respective groups of anagrams. Here’s how you can do it in Python: def group_anagrams(strs): anagrams = {} for word in strs: sorted_word = ''.join(sorted(word)) if sorted_word in anagrams: anagrams[sorted_word].append(word) else: anagrams[sorted_word] = [word] return list(anagrams.values()) # Example strs = ["eat", "tea", "tan", "ate", "nat", "bat"] print(group_anagrams(strs)) In this code:...

Question: Given an array of integer nums and an integer target, return indices of the two numbers such that they add up to the target. Answer: To solve this problem, you can use a dictionary to store the indices of the numbers you’ve seen so far. As you iterate through the array, you can check if the complement of the current number (target - current number) exists in the dictionary. If it does, you’ve found the two indices that add up to the target....

To solve the “valid anagram” problem, we need to determine if two given strings are anagrams of each other. Two strings are anagrams if they contain the same characters with the same frequencies. Here is a Python function that solves this problem using different approaches, followed by an analysis of each approach to find the best solution. Solution 1: Sorting def is_anagram(s, t): return sorted(s) == sorted(t) Explanation: Sorting: Sort both strings and compare them....

To determine if any value appears more than once in an integer array, the best approach is to use a set due to its optimal balance of time complexity, space complexity, and simplicity. Here’s a comprehensive solution and explanation: Solution def contains_duplicate(nums): seen = set() for num in nums: if num in seen: return True seen.add(num) return False Explanation Initialization: Create an empty set called seen. seen = set() Iteration: Loop through each element in the array....