Practice

LeetCode 10xx

LeetCode practice notes for problems 1000 through 1100, covering interval DP, sliding window, binary search, greedy, SQL, and more.

LeetCode

LeetCode practice notes.

LeetCode 09xx

LeetCode practice notes for problems 900 through 999, including A clear explanation of designing an iterator over a run-length encoded sequence without expanding it.

LeetCode 08xx

LeetCode practice notes for problems 800 through 899, including A clear explanation of finding the closest shorthand RGB color by rounding each color channel to the nearest repeated hexadecimal pair.

LeetCode 07xx

LeetCode practice notes for problems 700 through 799, including Search for a target value in a binary search tree and return the subtree rooted at the matching node.

LeetCode 00xx

LeetCode practice notes for problems 1 through 99, including A clear explanation of the Two Sum problem using brute force first, then an optimized hash map solution.

LeetCode 02xx

LeetCode practice notes for problems 200 through 299, including A clear explanation of counting connected groups of land cells in a grid using DFS or BFS.

LeetCode 01xx

LeetCode practice notes for problems 100 through 199, including A detailed guide to solving Same Tree with recursive DFS and structural comparison.

LeetCode 06xx

LeetCode practice notes for problems 600 through 699, including A clear digit dynamic programming solution for counting numbers whose binary representation does not contain consecutive ones.

LeetCode 05xx

LeetCode practice notes for problems 500 through 599, including A clear explanation of filtering words that can be typed using only one row of an American keyboard.

LeetCode 04xx

LeetCode practice notes for problems 400 through 499, including A clear explanation of finding the nth digit in the infinite integer sequence using digit groups and arithmetic.

LeetCode 03xx

LeetCode practice notes for problems 300 through 399, including A dynamic programming and patience sorting solution for finding the longest strictly increasing subsequence in an array.

Practice

Programming practice notes and algorithm problem explanations.