【动态规划】codeforces1155D Beautiful Array

D. Beautiful Array
time limit per test2 seconds
memory limit per test256 megabytes
inputstandard input
outputstandard output
You are given an array a consisting of n integers. Beauty of array is the maximum sum of some consecutive subarray of this array (this subarray may be empty). For example, the beauty of the array [10, -5, 10, -4, 1] is 15, and the beauty of the array [-3, -5, -1] is 0.

You may choose at most one consecutive subarray of a and multiply all values contained in this subarray by x. You want to maximize the beauty of array after applying at most one such operation.

Input
The first line contains two integers n and x (1≤n≤3⋅105,−100≤x≤100) — the length of array a and the integer x respectively.

The second line contains n integers a1,a2,…,an (−109≤ai≤109) — the array a.

Output
Print one integer — the maximum possible beauty of array a after multiplying all values belonging to some consecutive subarray x.

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