~/lc-grind

Check if two strings are valid anagrams by comparing their character frequencies—perfect for mastering hash tables, string manipulation, or sorting techniques!

Find the smallest substring in `s` that contains all characters of `t` (including duplicates), or return an empty string if no such window exists—solved efficiently using a sliding window and hash table approach.

Master the sliding window technique to solve this medium problem: find the longest substring with all identical characters by performing at most `k` replacements in the given string.

Master the sliding window technique to efficiently find the length of the longest substring without repeating characters in a given string.

Solve the 'Word Search' problem by using backtracking and DFS to check if a given word can be formed from adjacent letters in an m x n grid without reusing cells.

Learn how to rotate an n x n matrix by 90 degrees clockwise in-place, without using extra space, by strategically swapping and transposing elements.

Traverse an `m x n` matrix in a clockwise spiral order, returning all elements as a single list—perfect for mastering matrix manipulation and boundary handling!

Learn how to efficiently set entire rows and columns to zero in a matrix when encountering a zero element, with optimal space complexity solutions.

Learn how to reorder a linked list by interleaving nodes from the beginning and end (L0 → Ln → L1 → Ln-1 → …) using two pointers, a stack, or recursion—a classic medium-difficulty problem!

Master the two-pointer technique to efficiently remove the nth node from the end of a linked list in a single pass—perfect for sharpening your linked list manipulation skills!