{"data":[{"oj":"luogu","problem_id":"P3369","title":"【模板】普通平衡树","description":"同一道顺序统计题给出三种解法：离线坐标压缩 + Fenwick、Python 版 FHQ-Treap，以及 C++ 版 FHQ-Treap。","difficulty":"提高+/省选-","date":"2026-07-16 19:57","updated":"2026-10-07 12:15","toc":true,"tags":["树状数组","坐标压缩","有序多重集","Treap","python","cpp"],"showAtRbook":["bit","treap"],"favorite":true,"favorite_reason":"离线坐标压缩 + 树状数组即可完整实现普通平衡树的六个操作，说明顺序统计的本质是「前缀和 + 前缀选择」，不必手写平衡树。","categories":[],"pre":[{"oj":"luogu","problem_id":"P5250","reason":"B 的解法一（离线坐标压缩+Fenwick）直接复用 A 的这一步：小于 x 的数量定位第 count 小即前驱、kth 二进制提升取第 k 小，再叠加 A 未教的可重集合计数语义（排名、删除一个 x）；B 的 FHQ-Treap 解法不涉及此步。"},{"oj":"luogu","problem_id":"P2234","reason":"B 沿用 A 的坐标压缩加 Fenwick 前缀计数、kth 二进制提升查前驱后继这一步实现平衡树六操作"}],"common":[],"recommend":[],"source":"https://www.luogu.com.cn/problem/P3369","md_path":"luogu/P3369/index.md","url":"/problems/luogu/P3369","dateA":1784203020000,"updatedA":1791346500000,"aiNotes":[]}],"pagination":{"total":1,"page":1,"limit":20,"totalPages":1}}