题意 给出一个长度为\(n\)的数列和数字\(x\),经过最多一次操作将数列的一个子段的每个元素变为\(a[i]*x\),使该数列的最大子段和最大 分析 将这个数列分为3段考虑,第一段和第三段是未修改的,第二段是修改的子段 设\(dp[i][j]\)为第\(i\)个数字为第\(j+1\)段的最大子段和 三种转移方程 第一段:\(dp[i][0]=max(a[i],dp[i-1][0]+a[i])\) 第二段:\(dp[i][1]=max(a[i]*x,dp[i-1][0]+a[i]*x,dp[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…

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…

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…