对于长度为n的数组a,如果长度为n的数组s满足所有k的sk=(∑i=k−lowbit(k)+1kai)mod998244353,那么s称为a的树状数组。记作s=f(a)。 对于正整数k和数组a,fk(a)的定义如下: fk(a)={f(a)ifk=1f(fk−1(a))otherwise. 给你一个长度为n的数组b和一个正整数k。求满足0≤ai<998244353和fk(a...
Fenwicktree struct structfenwicktree{intn;vector<int>fn;voidinit(int_n){n=_n+1;fn.resize(n,0);}voidget(intx,intsum){for(x++;x<n;x+=(x&(-x))){fn[x]+=sum;}}// sum from 1 to idxint_sum(intx){intans=0;for(x++;x>0;x-=(x&(-x))){ans+=fn[x];}returnans;}ints...
Fenwick tree: initialization in O(N) By ATSTNG, history, 7 years ago, translation, Hi, CodeForces. Recently I decided to take a closer look at data structure called Fenwick tree or binary indexed tree. In this blogpost I will only consider Fenwick tree for sum, but everything stated ...
For an array aa of length nn, if an array ss of length nn satisfies sk=(∑i=k−lowbit(k)+1kai) mod 998 244 353sk=(i=k−lowbit(k)+1∑kai)mod998244353 for all kk, then ss is called the Fenwick Tree of aa. Let's denote it as s=f(a)s=f(a). For a posi...
CF1967C Fenwick Tree 树状数组,计数 非常好玩的题,考察对树状数组本质形态的理解。 Link:https://codeforces.com/contest/1967/problem/C 简述 对于数列 aa,定义数列 f(a)f(a) 为对数列 aa 建立的树状数组。即有: f(a)k=k∑i=k−lowbit(k)+1aif(a)k=∑i=k−lowbit(k)+1kai 给定TT 组...
F - Fenwick Tree Gym - 100623F (树状数组规律) http://codeforces.com/gym/100623/attachments Problem F. Fenwick TreeInput file: Output file: fenwick.outTime limit: 3 secondsMemory limit: 256 megabytesFenwick tree is a data structure effectively supporting prefix sum queries.For a number t ...
A Fenwick tree is just an array, $T[0 \dots N-1]$, where each element is equal to the sum of elements of $A$ in some range, $[g(i), i]$:$$T_i = \sum_{j = g(i)}^{i}{A_j}$$where $g$ is some function that satisfies $0 \le g(i) \le i$. We will define $...
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Fenwicktree struct struct fenwicktree{ int n; vector<int> fn; void init(int _n){ n = _n+1; fn.resize(n,0); } void get(int x,int sum){ for(x++;x<n;x+=(x&(-x))){ fn[x] += sum; } } // sum from 1 to idx int _sum(int x){ int ans = 0; for(x++;x>0;x...