PPaste!

#py2

n = input()
k = input()
assert 1 <= n <= 10**5
assert 1 <= k <= n
    
lis = []
for i in range(n):
    lis.append(input())
    
lis.sort()
sum_lis = []
for i in lis:
    assert 0 <= i <= 10**9
    
val = 1-k
answer = 0
    
sum_lis.append(lis[0])
    
for i in range(1,n):
    sum_lis.append(sum_lis[i-1]+lis[i])
    
for i in range(k):
    answer += val*lis[i]
    val += 2
    
final_answer = answer
for i in range(k,n):
    new_answer = answer + (k-1)*lis[i] + (k-1)*lis[i-k] - 2*(sum_lis[i-1]-sum_lis[i-k])
    final_answer = min(new_answer, final_answer)
    answer = new_answer
    
print final_answer

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#C++

#include<stdio.h>
#include<stdlib.h>
#include<algorithm>
#include<assert.h>
using namespace std;
#define Max_N 100001
typedef long long int ll;
long long int sum[Max_N];
int N,K,input[Max_N];
ll min(ll a,ll b)
{
    if(a>b)    return b;
    else return a;
}
int main()
{
    int val;
    scanf("%d%d",&N,&K);
    assert(1<=N && N<=100000);
    assert(1<=K && K<=N);
    for(int i=1;i<=N;i++)
    {
        scanf("%d",&input[i]);
        assert(0<=input[i] && input[i]<=1000000000);
    }
    input[0]=0;
    sort(input+1,input+N+1);
    sum[0]=0;
    for(int i=1;i<=N;i++)    sum[i]=input[i]+sum[i-1];
    
    val=1-K;
    ll answer=0,compare,previous;
    for(int i=1;i<=K;i++){
        answer+=(ll)val*input[i];
        val+=2;
    }
    //printf("%lld is answeer\n",answer);
    previous=answer;
    for(int i=K+1;i<=N;i++){
        compare=(ll)(K-1)*input[i];
        compare=previous + (ll)(K-1)*input[i] + (ll)(K-1)*input[i-K]-(ll)2*(sum[i-1]-sum[i-K]);
        answer=min(answer,compare);
        previous=compare;
    }
    printf("%lld\n",answer);
    return 0;
}