Medium

LeetCode note for Loud and Rich, rebuilt from the original learning note

LeetCode note for Find Eventual Safe States, rebuilt from the original learning note

LeetCode 3900 note: equal prefix differences mean balanced; a substring off by 2 also works if a swappable character exists outside, and keeping the two earliest positions per difference is enough

LeetCode 3899 note: check the triangle inequality first, compute the three angles with the law of cosines, and remember to sort them

LeetCode note for Minimum Height Trees, rebuilt from the original learning note

LeetCode note for Find All Possible Recipes from Given Supplies, rebuilt from the original learning note

LeetCode note for All Ancestors of a Node in a DAG, rebuilt from the original learning note

LeetCode note for Course Schedule II, rebuilt from the original learning note

LeetCode note for Course Schedule, rebuilt from the original learning note

LeetCode 522 note: the longest uncommon subsequence is always a whole string; check strings from longest to shortest, and the first that is not a subsequence of any other long-enough string is the answer

LeetCode 3885 note: a dict of current priorities plus a max-heap with lazy deletion, validated on pop

LeetCode 1023 note: two pointers character by character; anything beyond the pattern must be lowercase