Roma works in a company that sells TVs. Now he has to prepare a report for the last year.

Roma has got a list of the company's incomes. The list is a sequence that consists of n integers. The total income of the company is the sum of all integers in sequence. Roma decided to perform exactly k changes of signs of several numbers in the sequence. He can also change the sign of a number one, two or more times.

The operation of changing a number's sign is the operation of multiplying this number by -1.

Help Roma perform the changes so as to make the total income of the company (the sum of numbers in the resulting sequence) maximum. Note that Roma should perform exactlyk changes.

Input

The first line contains two integers n and k (1 ≤ n, k ≤ 105), showing, how many numbers are in the sequence and how many swaps are to be made.

The second line contains a non-decreasing sequence, consisting of n integers ai(|ai| ≤ 104).

The numbers in the lines are separated by single spaces. Please note that the given sequence is sorted in non-decreasing order.

Output

In the single line print the answer to the problem — the maximum total income that we can obtain after exactly k changes.

Examples

Input

3 2
-1 -1 1

Output

3

Input

3 1
-1 -1 1

Output

1

Note

In the first sample we can get sequence [1, 1, 1], thus the total income equals 3.

In the second test, the optimal strategy is to get sequence [-1, 1, 1], thus the total income equals 1.

变K次,而且本来数组就是有序的,想让最早的负数都变成,然后就只有如下可能:

1.K次变换结束后,仍存在负数

2.K次变换结束后,恰好无负数

3.K次变换未完成,无负数

前两种直接求和,因为每次对最小值取反,一定是最优解。

第三种,如果数组中有0,或者 剩余K为偶数,那么最优是保持原来数组的大小即为最优,K次全部作用于偶数,或作用于零,不改变数组大小。

另外一种情况,K次操作后必然至少会有一个值被取反,所以一定是最小的数字,时间允许,直接排序,干就完事。

#include<iostream>
#include<queue>
#include<algorithm>
#include<set>
#include<cmath>
#include<vector>
#include<map>
#include<stack>
#include<bitset>
#include<cstdio>
#include<cstring>
//---------------------------------Sexy operation--------------------------// #define cini(n) scanf("%d",&n)
#define cinl(n) scanf("%lld",&n)
#define cinc(n) scanf("%c",&n)
#define cins(s) scanf("%s",s)
#define coui(n) printf("%d",n)
#define couc(n) printf("%c",n)
#define coul(n) printf("%lld",n)
#define speed ios_base::sync_with_stdio(0)
#define file freopen("input.txt","r",stdin);freopen("output.txt","w",stdout)
//-------------------------------Actual option------------------------------// #define Swap(a,b) a^=b^=a^=b
#define Max(a,b) a>b?a:b
#define Min(a,b) a<b?a:b
#define mem(n,x) memset(n,x,sizeof(n))
#define mp(a,b) make_pair(a,b)
//--------------------------------constant----------------------------------// #define INF 0x3f3f3f3f
#define maxn 100010
#define esp 1e-9
using namespace std;
typedef long long ll;
typedef pair<int,int> PII;
//------------------------------Dividing Line--------------------------------//
int n,m;
int a[maxn];
int main()
{
cini(m),cini(n);
int t=0;
for(int i=0;i<m;i++)
{
cin>>a[i];
if(a[i]<0){
if(a[i]==0) t=i;
if(n)
{
a[i]=-a[i];
n--;
}
} }
long long ans=0;
if(t==0&&n!=0&&n%2==1)
{
sort(a,a+m);
a[0]=-a[0];
for(int i=0;i<m;i++) ans+=a[i];
cout<<ans<<endl;
return 0; }
else {
for(int i=0;i<m;i++) ans+=a[i];
cout<<ans<<endl;
return 0; } }

CodeForces - 262B的更多相关文章

  1. python爬虫学习(5) —— 扒一下codeforces题面

    上一次我们拿学校的URP做了个小小的demo.... 其实我们还可以把每个学生的证件照爬下来做成一个证件照校花校草评比 另外也可以写一个物理实验自动选课... 但是出于多种原因,,还是绕开这些敏感话题 ...

  2. 【Codeforces 738D】Sea Battle(贪心)

    http://codeforces.com/contest/738/problem/D Galya is playing one-dimensional Sea Battle on a 1 × n g ...

  3. 【Codeforces 738C】Road to Cinema

    http://codeforces.com/contest/738/problem/C Vasya is currently at a car rental service, and he wants ...

  4. 【Codeforces 738A】Interview with Oleg

    http://codeforces.com/contest/738/problem/A Polycarp has interviewed Oleg and has written the interv ...

  5. CodeForces - 662A Gambling Nim

    http://codeforces.com/problemset/problem/662/A 题目大意: 给定n(n <= 500000)张卡片,每张卡片的两个面都写有数字,每个面都有0.5的概 ...

  6. CodeForces - 274B Zero Tree

    http://codeforces.com/problemset/problem/274/B 题目大意: 给定你一颗树,每个点上有权值. 现在你每次取出这颗树的一颗子树(即点集和边集均是原图的子集的连 ...

  7. CodeForces - 261B Maxim and Restaurant

    http://codeforces.com/problemset/problem/261/B 题目大意:给定n个数a1-an(n<=50,ai<=50),随机打乱后,记Si=a1+a2+a ...

  8. CodeForces - 696B Puzzles

    http://codeforces.com/problemset/problem/696/B 题目大意: 这是一颗有n个点的树,你从根开始游走,每当你第一次到达一个点时,把这个点的权记为(你已经到过不 ...

  9. CodeForces - 148D Bag of mice

    http://codeforces.com/problemset/problem/148/D 题目大意: 原来袋子里有w只白鼠和b只黑鼠 龙和王妃轮流从袋子里抓老鼠.谁先抓到白色老鼠谁就赢. 王妃每次 ...

随机推荐

  1. Java 给 PowerPoint 文档添加背景颜色和背景图片

    在制作Powerpoint文档时,背景是非常重要的,统一的背景能让Powerpoint 演示文稿看起来更加干净美观.本文将详细讲述如何在Java应用程序中使用免费的Free Spire.Present ...

  2. JQUERY滚动加载

    $(document).height():整个网页的高度$(window).height():浏览器可视窗口的高度$(window).scrollTop():浏览器可视窗口顶端距离网页顶端的高度(垂直 ...

  3. ubuntu 虚拟机复制后打开蓝屏解决办法

    sudo apt-get install xserver-xorg-lts-utopic sudo dpkg-reconfigure xserver-xorg-lts-utopic reboot

  4. ln -s 软链接命令

    所有对软链接link_name的操作都是对目录或文件dir_file的操作 ln -s [dir_file] [link_name]

  5. 【python实现卷积神经网络】定义训练和测试过程

    代码来源:https://github.com/eriklindernoren/ML-From-Scratch 卷积神经网络中卷积层Conv2D(带stride.padding)的具体实现:https ...

  6. 视频图文教学 - 用最快的速度把 DotNet Core Blazor 程序安装到 树莓派中 并且用网页控制 GPIO 闪灯

    前言 dotnet core 在3.0时代已经发展得很好. 尤其是在跨平台方面更已经是达到了很实用的阶段. 作为 dotnet 程序员, 应该对 Linux 有充分的了解, 也可以在业余时间玩玩硬件, ...

  7. Python导出数据到Excel表格-NotImplementedError: formatting_info=True not yet implemented

    在使用Python写入数据到Excel表格中时出现报错信息记录:“NotImplementedError: formatting_info=True not yet implemented” 报错分析 ...

  8. G - Messy codeforces1262C

    题目大意: 输入n和m,n是n个字符,m是m个前缀.对前缀的规定可以配对的括号.比如(),,((()))等等.在输入n个括号字符,对这个n个字符,通过交换使其满足m个前缀.交换次数不限,规则想当与re ...

  9. SpringCloud(五)学习笔记之Hystrix

    在微服务架构中多层服务之间会相互调用,如果其中有一层服务故障了,可能会导致一层服务或者多层服务故障,从而导致整个系统故障.这种现象被称为服务雪崩效应. Hystrix组件就可以解决此类问题,Hystr ...

  10. Java类的使用

    在一个Java文件中写两个类:一个基本的类,一个测试类.注意:文件名称和测试类名称一致. 如何使用呢?创建对象使用.如何创建对象呢?格式:类名 对象名 = new 类名(); Student s = ...