dp--最大区间和变形-cf-1155D

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 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 aa and multiply all values contained in this subarray by xx. You want to maximize the beauty of array after applying at most one such operation.

Input

The first line contains two integers nn and xx (1≤n≤3⋅105,−100≤x≤1001≤n≤3⋅105,−100≤x≤100) — the length of array aa and the integer xxrespectively.

The second line contains nn integers a1,a2,…,ana1,a2,…,an (−109≤ai≤109−109≤ai≤109) — the array aa.

Output

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

Examples

input

Copy

5 -2
-3 8 -2 1 -6

output

Copy

22

input

Copy

12 -3
1 3 3 7 1 3 3 7 1 3 3 7

output

Copy

42

input

Copy

5 10
-1 -2 -3 -4 -5

output

Copy

0

Note

In the first test case we need to multiply the subarray [-2, 1, -6], and the array becomes [-3, 8, 4, -2, 12] with beauty 22 ([-3, 8, 4, -2, 12]).

In the second test case we don't need to multiply any subarray at all.

In the third test case no matter which subarray we multiply, the beauty of array will be equal to 0.

状态转移方程如下

#include <iostream>
#include <cstdio>
#include <string>
#include <cstring>
#include <cmath>
#include <sstream>
#include <algorithm>
#include <set>
#include <map>
#include <vector>
#include <queue>
#include <iomanip>
#include <stack>
#include <climits>
#include <fstream> using namespace std; typedef long long LL;
const int INF = 0x3f3f3f3f;
const int N = 300005;
const int MOD = 1e9 + 7; #define F(i, l, r) for(int i = l;i <= (r);++i)
#define RF(i, l, r) for(int i = l;i >= (r);--i) int main()
{
LL n, m, t, ans = 0, p = 0, sum1 = 0, sum2 = 0;
cin >> n >> m;
F(i, 1, n)
{
cin >> t;
sum1 = max(sum1 + t, 0ll);//d[i][0] = max(0ll,d[i-1][0]+a[i]);
sum2 = max(sum2 + m * t, sum1);//d[i][1] = max( 0ll, max(d[i-1][0],d[i-1][1])+a[i]*x);
p = max(p + t, sum2);// d[i][2] = max( 0ll, max(d[i-1][0], max(d[i-1][1],d[i-1][2]) )+ a[i]);
ans = max(ans, p);
}
cout << ans << endl;
return 0;
}

dp--最大区间和变形-cf-1155D的更多相关文章

  1. Codeforces Round #354 (Div. 2)-C. Vasya and String,区间dp问题,好几次cf都有这种题,看来的好好学学;

    C. Vasya and String time limit per test 1 second memory limit per test 256 megabytes input standard ...

  2. hihocoder1636 Pangu and Stones(区间DP(石子合并变形))

    题目链接:http://hihocoder.com/problemset/problem/1636 题目大意:有n堆石头,每次只能合并l~r堆,每次合并的花费是要合并的石子的重量,问你合并n堆石子的最 ...

  3. Vijos1451圆环取数[环形DP|区间DP]

    背景 小K攒足了路费来到了教主所在的宫殿门前,但是当小K要进去的时候,却发现了要与教主守护者进行一个特殊的游戏,只有取到了最大值才能进去Orz教主…… 描述 守护者拿出被划分为n个格子的一个圆环,每个 ...

  4. poj 2184 Cow Exhibition(dp之01背包变形)

    Description "Fat and docile, big and dumb, they look so stupid, they aren't much fun..." - ...

  5. dp之区间:Light oj 1422 Halloween Costumes

    http://lightoj.com/volume_showproblem.php?problem=1422 题意:给你n天需要穿的衣服的样式,每次可以套着穿衣服,脱掉的衣服就不能再穿了,问至少要带多 ...

  6. Codeforces Round #336 (Div. 2)B 暴力 C dp D 区间dp

    B. Hamming Distance Sum time limit per test 2 seconds memory limit per test 256 megabytes input stan ...

  7. 区间DP(区间最优解)题目讲解总结

    1:给出一个括号字符串,问这个字符串中符合规则的最长子串的长度. [分析]区间DP要覆盖整个区间,那么要求所有情况的并集. 先想出状态方程: dp[i][j]:i ~ j区间内最大匹配数目 输出:dp ...

  8. 「DP」区间dp

    区间dp? 状态设计为描述一段区间的dp. eg:f[i][j]表示从 i 到 j 这个区间上的最优值.

  9. lightoj 1422【区间DP·分类区间首元素的情况】

    题意: 给你n天分别要穿的衣服种类,可以套着穿, 一旦脱下来就不能再穿,求n天至少要几件. 思路: 区间DP dp[i][j]代表i到j需要至少几件衣服 第i天的衣服在第i天穿上了,dp[i][j]= ...

随机推荐

  1. myeclipse 快捷键,从步骤开始的大括号定位到匹配方法结束的大括号

    myeclipse 快捷键,从方法开始的大括号定位到匹配方法结束的大括号转至匹配的括号 Ctrl+Shift+P ctr+shift+r   文件名搜索文件 ctr+h           搜索文件里 ...

  2. swift 动画

    // //  ViewController.swift //  Anamation // //  Created by su on 15/12/9. //  Copyright © 2015年 tia ...

  3. Google’s Project Tango is shutting down because ARCore is already here

    https://www.theverge.com/2017/12/15/16782556/project-tango-google-shutting-down-arcore-augmented-rea ...

  4. (匹配 Hopcroft-Karp算法)Rain on your Parade -- Hdu --2389

    链接: http://acm.hdu.edu.cn/showproblem.php?pid=2389 不能用匈牙利,会TEL的,用Hopcroft-Karp Hopcroft-Karp课件 以前是寻找 ...

  5. REQUEST的TRACE文件

    --REQUEST的TRACE文件 SELECT    'Trace Name: '       || DEST.VALUE       || '/'       || LOWER (DBNM.VAL ...

  6. yum反查某个命令或so库在哪个包里面

    yum whatprovides "*/XXX.so.1"

  7. 扫描指定ip的端口(C#)

    class PingExam { public static void Main() { Ping ping = new Ping(); string ip = "192.168.1.43& ...

  8. asp.net 导出 Excel

    /// <summary> /// List 数据导出Excel /// </summary> /// <param name="list">数 ...

  9. DataGridView添加一行数据、全选、取消全选、清空数据、删除选中行

    .net 2005下的Windows Form Application,一个DataGridView控件和4个Button,界面设置如下:         代码如下,有注解,相信大家都看得明白:   ...

  10. WPF定时刷新UI界面

    代码: using NHibernate.Criterion; using System; using System.Collections.Generic; using System.Collect ...