Binary-Indexed-Tree onhttps://h30306.github.io/blog/tags/binary-indexed-tree/Recent content in Binary-Indexed-Tree onHugo -- gohugo.ioenhwork0511@gmail.com (Wei Yi Chung)hwork0511@gmail.com (Wei Yi Chung)© 2026 Wei Yi ChungWed, 21 Oct 2026 00:00:00 +0000Segment Tree and Fenwick Treehttps://h30306.github.io/blog/algorithm/segment-tree/Wed, 21 Oct 2026 00:00:00 +0000hwork0511@gmail.com (Wei Yi Chung)https://h30306.github.io/blog/algorithm/segment-tree/Point updates with range queries: a Fenwick tree (binary indexed tree) jumps by i & -i, and a segment tree recursively halves the range; both take O(log n) per operationLeetCode 4051: Count Subarrays with Distant Sumshttps://h30306.github.io/blog/leetcode/leetcode-4051/Mon, 19 Oct 2026 00:00:00 +0000hwork0511@gmail.com (Wei Yi Chung)https://h30306.github.io/blog/leetcode/leetcode-4051/LeetCode 4051 note: prefix sums, complement counting, range counting, and the k = 0 edge caseLeetCode 315: Count of Smaller Numbers After Selfhttps://h30306.github.io/blog/leetcode/leetcode-315/Sun, 18 Oct 2026 00:00:00 +0000hwork0511@gmail.com (Wei Yi Chung)https://h30306.github.io/blog/leetcode/leetcode-315/LeetCode 315 note: merge sort with indices, plus a BIT solutionLeetCode 2193: Minimum Number of Moves to Make Palindromehttps://h30306.github.io/blog/leetcode/leetcode-2193/Wed, 02 Sep 2026 00:00:00 +0000hwork0511@gmail.com (Wei Yi Chung)https://h30306.github.io/blog/leetcode/leetcode-2193/LeetCode 2193 note: greedily fix the outer pair: take the last character and swap its leftmost partner to the front, costing that index; the unpaired character ends in the middle, costing its distance thereLeetCode 327: Count of Range Sumhttps://h30306.github.io/blog/leetcode/leetcode-327/Sat, 01 Aug 2026 00:00:00 +0000hwork0511@gmail.com (Wei Yi Chung)https://h30306.github.io/blog/leetcode/leetcode-327/LeetCode 327 note: prefix sums plus merge sort counting with two pointers bounding a range, and a log of retyping it over a dozen timesLeetCode 307: Range Sum Query - Mutablehttps://h30306.github.io/blog/leetcode/leetcode-307/Fri, 19 Jun 2026 00:00:00 +0000hwork0511@gmail.com (Wei Yi Chung)https://h30306.github.io/blog/leetcode/leetcode-307/LeetCode 307 note: point updates with range sums make prefix sums O(n) per update; a segment tree or Fenwick tree makes both operations O(log n)