Binary-Search-Tree

LeetCode 703 note: keep a min-heap of size k; its top is the k-th largest

LeetCode 700 note: go left when the node is larger, right when smaller, and return the node when found

LeetCode 530 note: a BST’s in-order is ascending, so the minimum difference is between in-order neighbors; remember the previous value and compare

LeetCode 501 note: a BST’s in-order is sorted, so equal values are contiguous; count the current run during in-order, resetting the answer on a new maximum and appending on a tie

LeetCode 235 note: go left when both p and q are smaller, right when both are larger; otherwise (split, or one is the node itself) this node is the LCA

LeetCode 108 note: the middle element becomes the root and each half recurses; the halves differ by at most one, so the tree is balanced