https://h30306.github.io/blog/tags/binary-search-tree/Recent content in Binary-Search-Tree onHugo -- gohugo.ioenhwork0511@gmail.com (Wei Yi Chung)hwork0511@gmail.com (Wei Yi Chung)© 2026 Wei Yi ChungSun, 25 Oct 2026 00:00:00 +0000https://h30306.github.io/blog/leetcode/leetcode-449/Sun, 25 Oct 2026 00:00:00 +0000hwork0511@gmail.com (Wei Yi Chung)https://h30306.github.io/blog/leetcode/leetcode-449/LeetCode 449 note: for a BST, pre-order without null markers is enough; deserialize recursively with bounds in O(n)https://h30306.github.io/blog/leetcode/leetcode-450/Sun, 25 Oct 2026 00:00:00 +0000hwork0511@gmail.com (Wei Yi Chung)https://h30306.github.io/blog/leetcode/leetcode-450/LeetCode 450 note: once the node is found: with zero or one child, splice the child in; with two, copy the right subtree’s minimum and delete that nodehttps://h30306.github.io/blog/leetcode/leetcode-99/Sun, 25 Oct 2026 00:00:00 +0000hwork0511@gmail.com (Wei Yi Chung)https://h30306.github.io/blog/leetcode/leetcode-99/LeetCode 99 note: find the inversions in the in-order sequence: the earlier node of the first inversion and the later node of the last one were swappedhttps://h30306.github.io/blog/leetcode/leetcode-173/Sat, 24 Oct 2026 00:00:00 +0000hwork0511@gmail.com (Wei Yi Chung)https://h30306.github.io/blog/leetcode/leetcode-173/LeetCode 173 note: flattening to an array is simple but uses O(n) space; the follow-up keeps the left spine on a stack for amortized O(1) and O(h) spacehttps://h30306.github.io/blog/leetcode/leetcode-701/Sat, 24 Oct 2026 00:00:00 +0000hwork0511@gmail.com (Wei Yi Chung)https://h30306.github.io/blog/leetcode/leetcode-701/LeetCode 701 note: walk down the BST to an empty spot and attach the new node; an empty tree must return the new nodehttps://h30306.github.io/blog/leetcode/leetcode-1373/Thu, 10 Sep 2026 00:00:00 +0000hwork0511@gmail.com (Wei Yi Chung)https://h30306.github.io/blog/leetcode/leetcode-1373/LeetCode 1373 note: a post-order traversal returns (sum, min, max, is_bst); a node roots a BST when the left max < its value < the right minhttps://h30306.github.io/blog/leetcode/leetcode-109/Sat, 19 Nov 2022 00:00:00 +0000hwork0511@gmail.com (Wei Yi Chung)https://h30306.github.io/blog/leetcode/leetcode-109/LeetCode 109 note: take the middle found with fast and slow pointers as the root and recurse on both halves; the height balances naturallyhttps://h30306.github.io/blog/leetcode/leetcode-230/Sat, 29 Oct 2022 00:00:00 +0000hwork0511@gmail.com (Wei Yi Chung)https://h30306.github.io/blog/leetcode/leetcode-230/LeetCode 230 note: a BST’s in-order traversal is ascending, so stop an iterative in-order walk at the k-th nodehttps://h30306.github.io/blog/leetcode/leetcode-98/Sat, 29 Oct 2022 00:00:00 +0000hwork0511@gmail.com (Wei Yi Chung)https://h30306.github.io/blog/leetcode/leetcode-98/LeetCode 98 note: every node has a valid range (low, high); going left the upper bound becomes the node and going right the lower bound does; comparing parent and child is not enoughhttps://h30306.github.io/blog/leetcode/leetcode-938/Mon, 26 Sep 2022 00:00:00 +0000hwork0511@gmail.com (Wei Yi Chung)https://h30306.github.io/blog/leetcode/leetcode-938/LeetCode 938 note: prune with the BST order, going only right below low and only left above high, adding nodes inside the rangehttps://h30306.github.io/blog/leetcode/leetcode-897/Sun, 25 Sep 2022 00:00:00 +0000hwork0511@gmail.com (Wei Yi Chung)https://h30306.github.io/blog/leetcode/leetcode-897/LeetCode 897 note: in-order traversal appending nodes to a right-only chain with left children cleared; keep the dummy separate from the moving tailhttps://h30306.github.io/blog/leetcode/leetcode-783/Tue, 06 Sep 2022 00:00:00 +0000hwork0511@gmail.com (Wei Yi Chung)https://h30306.github.io/blog/leetcode/leetcode-783/LeetCode 783 note: a BST’s in-order is ascending, so the minimum difference is between in-order neighbors; remember the previous value and comparehttps://h30306.github.io/blog/leetcode/leetcode-700/Wed, 31 Aug 2022 00:00:00 +0000hwork0511@gmail.com (Wei Yi Chung)https://h30306.github.io/blog/leetcode/leetcode-700/LeetCode 700 note: go left when the node is larger, right when smaller, and return the node when foundhttps://h30306.github.io/blog/leetcode/leetcode-703/Wed, 31 Aug 2022 00:00:00 +0000hwork0511@gmail.com (Wei Yi Chung)https://h30306.github.io/blog/leetcode/leetcode-703/LeetCode 703 note: keep a min-heap of size k; its top is the k-th largesthttps://h30306.github.io/blog/leetcode/leetcode-501/Thu, 25 Aug 2022 00:00:00 +0000hwork0511@gmail.com (Wei Yi Chung)https://h30306.github.io/blog/leetcode/leetcode-501/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 tiehttps://h30306.github.io/blog/leetcode/leetcode-530/Thu, 25 Aug 2022 00:00:00 +0000hwork0511@gmail.com (Wei Yi Chung)https://h30306.github.io/blog/leetcode/leetcode-530/LeetCode 530 note: a BST’s in-order is ascending, so the minimum difference is between in-order neighbors; remember the previous value and comparehttps://h30306.github.io/blog/leetcode/leetcode-235/Mon, 22 Aug 2022 00:00:00 +0000hwork0511@gmail.com (Wei Yi Chung)https://h30306.github.io/blog/leetcode/leetcode-235/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 LCAhttps://h30306.github.io/blog/leetcode/leetcode-108/Tue, 16 Aug 2022 00:00:00 +0000hwork0511@gmail.com (Wei Yi Chung)https://h30306.github.io/blog/leetcode/leetcode-108/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