LeetCode

LeetCode 3909 note: walk to the peak and sum each side; the peak belongs to both, so including it or not does not change the comparison

LeetCode 3908 note: convert to a string and check that it contains x but does not start with x

LeetCode note for Coin Change, rebuilt from the original learning note

LeetCode note for House Robber II, rebuilt from the original learning note

LeetCode note for Path With Minimum Effort, rebuilt from the original learning note

LeetCode note for Climbing Stairs, rebuilt from the original learning note

LeetCode 3906 note: the range reaches 9 × 10^15, so no per-number checks; a digit DP carries both lower and upper tight flags, plus the previous digit on the path since path cells must be non-decreasing

LeetCode 3905 note: multi-source BFS one layer at a time, collecting the maximum color per cell before writing the layer back

LeetCode 3904 note: the first index where the prefix maximum minus the suffix minimum is <= k; build the suffix minimum right to left first

LeetCode 3903 note: the first index where the prefix maximum minus the suffix minimum is <= k; build the suffix minimum right to left first

LeetCode note for Swim in Rising Water, rebuilt from the original learning note

LeetCode 1514 note: multiplying probabilities only shrinks them, so Dijkstra applies; prune with <=