做法 \(f_{i,0}\)表示以\(i\)结尾未操作时的最大值 \(f_{i,1}\)表示以\(i\)结尾正在操作时的最大值 \(f_{i,2}\)表示以\(i\)结尾已结束操作时的最大值 Code #include<bits/stdc++.h> typedef long long LL; const int maxn=1e6+9; LL ans,n,x; LL a[maxn],f[maxn][3]; int main(){ std::cin>>n>>x; for(L…

CF115DBeautiful Array 题目大意:给一个有n个元素的a数组,可以选择其中一个区间的所有数都乘上x,也可以不选,求最大子序列和. 如果没有前面的操作,就是只求最大子序列和,我们都知道就一个贪心的思路,当目前序列的和<0了,我们就当它为0,因为它对后面的序列只有负的贡献,完全不会使和增大,只会使和减少.所以我们从左往右,和从右往左,分别处理出没有乘x的最大子序列和maxl和maxr,这样的话,如果我们在区间[l,r]内乘x,那么相应的答案就是(sum[r]-sum[l-1])*x…

Educational Codeforces Round 63 (Rated for Div. 2) D. Beautiful Array time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output You are given an array aa consisting of nn integers. Beauty of array i…

For some fixed N, an array A is beautiful if it is a permutation of the integers 1, 2, ..., N, such that: For every i < j, there is no k with i < k < j such that A[k] * 2 = A[i] + A[j]. Given N, return any beautiful array A.  (It is guaranteed th…

2019-04-06 16:09:56 问题描述: 问题求解: 本题还是挺有难度的,主要是要考虑好如何去进行构造. 首先考虑到2 * A[i] = A[j] + A[k],那么j,k就必须是同奇同偶,否则它们的和必为奇数,显然等式不成立. 那么如果我们将N的数组分成两个部分,一部分全奇数,一部分全偶数,并且这两个部分是Beautiful Array,那么将它们concat一下,得到的也是Beautiful Array. 那么如何得到这两个部分呢? 这就需要一些数学的证明了,很容易证明得到漂亮数组…

For some fixed N, an array A is beautiful if it is a permutation of the integers 1, 2, ..., N, such that: For every i < j, there is no k with i < k < j such that A[k] * 2 = A[i] + A[j]. Given N, return any beautiful array A. (It is guaranteed tha…

D. Beautiful Array time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output You are given an array aa consisting of nn integers. Beauty of array is the maximum sum of some consecutive subarray of t…

For some fixed N, an array A is beautiful if it is a permutation of the integers 1, 2, ..., N, such that: For every i < j, there is no k with i < k < j such that A[k] * 2 = A[i] + A[j]. Given N, return any beautiful array A.  (It is guaranteed th…

I. Beautiful Array 2017- BUPT Collegiate Programming Contest - sync 时间限制 1000 ms 内存限制 65536 KB 题目描述 We call an array "beautiful array of level L", when all its adjacent number pairs have common factor greater than or equal to L. Obviously, a &qu…

For some fixed N, an array A is beautiful if it is a permutation of the integers 1, 2, ..., N, such that: For every i < j, there is no k with i < k < j such that A[k] * 2 = A[i] + A[j]. Given N, return any beautiful array A.  (It is guaranteed th…