int lower_bound(int k) int pos = 1; while (pos < N) if (tree[pos<<1] < k) k -= tree[pos<<1]; pos = pos<<1 else pos = pos<<1;
The zkw segment tree is an elegant, highly efficient alternative to the classic recursive segment tree. Its iterative nature yields simpler code, lower constant factor, and smaller memory footprint. While it does not simplify lazy propagation, it excels in point update / range query scenarios and is an essential tool for performance‑sensitive applications. zkw线段树
虽然 ZKW 线段树的区间修改写法较难掌握，但仅凭其简洁的单点修改和查询代码，它就足以成为你算法工具箱中的一把利剑。 int lower_bound(int k) int pos = 1; while
int n, N = 1; while (N < n) N <<= 1; vector<int> tree(2*N, 0); while (pos <