Hard

LeetCode 2781 note: forbidden words are at most 10 long, so each right end checks only the last 10 suffixes; on a match push the left end past it, using the shortest match (the rightmost start)

LeetCode 2009 note: the result is n consecutive integers; after deduplicating and sorting, a sliding window finds the most distinct values within a span of n - 1, and the rest must change

LeetCode 2106 note: the harvest is always a contiguous block of fruits; covering [L, R] takes (R - L) + min(|start - L|, |R - start|) steps, so slide a window over the fruits array

LeetCode 1458 note: a two-prefix DP; dp[i][j] either pairs nums1[i] with nums2[j] (extending dp[i-1][j-1] or starting fresh) or skips one of them

LeetCode 220 note: with bucket size valueDiff + 1, two numbers in one bucket always qualify, so only the two neighboring buckets need checking; the window keeps the latest indexDiff numbers, so each bucket holds at most one

LeetCode 2953 note: split where neighboring letters differ by more than 2; in each segment enumerate the number of distinct letters d, slide a fixed window of d × k, and track how many letters appear exactly k times

LeetCode 2156 note: the first character has weight p^0, so sliding right to left needs only multiply by p, add the new character, and subtract the outgoing one times p^k; the modulus may not be prime, so no modular inverse

Solving the Largest Rectangle in Histogram problem using monotonic stack approach

Three approaches: brute force, counting optimization, and sliding window over word-length offsets.

LeetCode 2709 note: every pair of indices connects ⇔ one component; factor with SPF and union each number with its prime factors in Union-Find, treating 1 specially

LeetCode Problem Solving - Variable Size Sliding Window with Character Counting

LeetCode 135 note: one pass left to right for the left neighbor, one right to left for the right neighbor, and give each child the larger of the two