题意: 有n个数的一个数组a,有两个操作: 1 l r:查询区间[l,r]内$a[l]*(r-l+1)+a[l+1]*(r-l)+a[l+2]*(r-l-1)+\cdots+a[r-1]*2+a[r]$ 2 l r:将a[l]修改为r n<=1e5,  a[i]<=1e9 思路: 预处理出前缀和s[i], 则操作1变为查询$s[l]+s[l+1]+..+s[r]-(r-l+1)*s[l-1]$ 为防止爆ll(其实也不会爆的)可以在查询操作力就提前减去s[l-1] 坑点来了..操作2即区间s(l…

题目链接: https://nanti.jisuanke.com/t/31458 题解: 建立两个树状数组,第一个是,a[1]*n+a[2]*(n-1)....+a[n]*1;第二个是正常的a[1],a[2],a[3]...a[n] #include "bits/stdc++.h" using namespace std; #define ll long long const int MAXN=1e5+10; ll sum[MAXN],ans[MAXN]; ll num[MAXN];…

题意:给你数组a,有两个操作 1 l r,计算l到r的答案:a[l]×L+a[l+1]×(L−1)+⋯+a[r−1]×2+a[r] (L is the length of [ l, r ] that equals to r - l + 1),或者 2 i b:把第i个换成b 思路:用一个树状数组存i的前缀和,再用一个树状数组存(n - i + 1)*a[ i ]的前缀和,这样算出后面那个的区间差减去前一个的区间差的某个倍数就会成为答案. 代码: #include<queue> #include…

Output For each question, output one line with one integer represent the answer. 样例输入 5 3 1 2 3 4 5 1 1 3 2 5 0 1 4 5 样例输出 10 8两个树状数组一个维护a[i]前缀合,一个维护(n-i+1)*a[i]前缀和. #include <iostream> #include <algorithm> #include <cstring> #include &l…

题目链接:https://nanti.jisuanke.com/t/31460 Ryuji is not a good student, and he doesn't want to study. But there are n books he should learn, each book has its knowledge $a[i]$. Unfortunately, the longer he learns, the fewer he gets. That means, if he re…

Ryuji is not a good student, and he doesn't want to study. But there are n books he should learn, each book has its knowledge a[i]a[i]. Unfortunately, the longer he learns, the fewer he gets. That means, if he reads books from ll to rr, he will get a…

https://nanti.jisuanke.com/t/38228 题意给你一个序列,对于每个连续子区间,有一个价值,等与这个区间和×区间最小值,求所有子区间的最大价值是多少. 分析:我们先用单调栈预处理 区间 [L[i] , R[i] ] 最小值为a[i] , 的L[i] , R[i] ; 首先我们明白 , 如果a[i] >0 那 [L[i] , R[i] ] , 里面的数都是正数 , 所以应该全选 : a[i] < 0 , 那我们 应该在[L[i]-1 , i-1] 这里面找到前缀和最大…

死于update的一个long long写成int了 真的不想写过程了 ******** 树状数组,一个平的一个斜着的,怎么斜都行 题库链接:https://nanti.jisuanke.com/t/31460 #include <iostream> #include <cstring> #define ll long long #define lowbit(x) (x & -x) using namespace std; ; int n, m; ll t[maxn]; l…

262144K   Ryuji is not a good student, and he doesn't want to study. But there are n books he should learn, each book has its knowledge a[i]a[i]. Unfortunately, the longer he learns, the fewer he gets. That means, if he reads books from ll to rr, he…

https://nanti.jisuanke.com/t/31460 题意 两个操作.1:查询区间[l,r]的和,设长度为L=r-l+1, sum=a[l]*L+a[l+1]*(L-1)+...+a[r].2:将第a个位置修改为b. 分析 变形一下,sum=a[l]*(r-l+1)+a[l+1]*(r-(l+1)-1)+...+a[r](r-r+1)=(r+1)*a[l]-a[l]*l.因此,可维护两个树状数组计算.至于更新操作,实质就是看变化前后的差值,变大就相当与加上差值,否则就是减.注意用…