hihoCoder 1595 : Numbers

Description

You are given n constant integers c[1], c[2], ..., c[n] and an integer k. You are to assign values to 2k integer variables, x[1], x[2], ..., x[k], y[1], y[2], ..., y[k], such that,

(1) For each 1 ≤ i ≤ k, x[i] ≤ y[i] holds,

(2) For each 1 ≤ i ≤ n, exists at least one such j (1 ≤ j ≤ k) that x[j] ≤ c[i] ≤ y[j].

Please find the minimum value of S=(y[1]+y[2]+...+y[k])-(x[1]+x[2]+...+x[k]).

Input

First line contains two integers n, k. (1 ≤ n, k ≤ 100000)

Following n lines contain integers c[1], c[2], ..., c[n]. (-1000000000 ≤ c[i] ≤ 1000000000)

Output

Output the minimum value of integer S.

Sample Hint

x[1]=-5, y[1]=4,

x[2]=10, y[2]=10.

http://hihocoder.com/contest/challenge31/solution/1201723

比赛中唯一让人感到美好的题目

按从小到大排序

定义一个区间大小为最大减最小

那么题目就是要把n个数分为k个区间，使和最小

贪心，一开始只分出1～n一个区间，后面将k-1个相邻差最大的值减去

#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;
int n,k,c[100001],d[100001];
long long ans;
bool cmp(int a,int b)
{
    return a>b;
}
int main()
{int i;
    cin>>n>>k;
    for (i=1;i<=n;i++)
    {
        scanf("%d",&c[i]);
    }
    sort(c+1,c+n+1);
    ans=c[n]-c[1];
    for (i=1;i<n;i++)
    d[i]=c[i+1]-c[i];
    sort(d+1,d+n,cmp);
    for (i=1;i<=k-1;i++)
    {
        ans-=d[i];
    }
    cout<<ans;
}