1 #include<cstdio> 2 #include<cstdlib> 3 #include<cmath> 4 #include<cstring> 5 #include<algorithm> 6 #include<iostream> 7 #include<vector> 8 #include<map> 9 #include<set>10 #include<queue>11 #include<string>12 #define inf 100000000013 #define maxn 200000+514 #define maxm 100000+515 #define eps 1e-1016 #define ll long long17 #define pa pair<int,int>18 #define for0(i,n) for(int i=0;i<=(n);i++)19 #define for1(i,n) for(int i=1;i<=(n);i++)20 #define for2(i,x,y) for(int i=(x);i<=(y);i++)21 #define for3(i,x,y) for(int i=(x);i>=(y);i--)22 #define for4(i,x) for(int i=head[x],y=e[i].go;i;i=e[i].next,y=e[i].go)23 #define mod 100000000724 using namespace std;25 inline int read()26 {27     int x=0,f=1;char ch=getchar();28     while(ch<‘0‘||ch>‘9‘){if(ch==‘-‘)f=-1;ch=getchar();}29     while(ch>=‘0‘&&ch<=‘9‘){x=10*x+ch-‘0‘;ch=getchar();}30     return x*f;31 }32 int n,m,a[maxn],l[maxn],r[maxn];33 priority_queue<pa>q;34 int main()35 {36     freopen("input.txt","r",stdin);37     freopen("output.txt","w",stdout);38     n=read();m=read();39     if(m>n>>1){printf("Error!\n");return 0;}40     for1(i,n)a[i]=read(),l[i]=i-1,r[i]=i+1,q.push(pa(a[i],i));41     l[1]=n;r[n]=1;42     int ans=0;43     for1(i,m)44     {45         while(!q.empty()&&q.top().first!=a[q.top().second])q.pop();46         int x=q.top().second;q.pop();47         ans+=a[x];48         a[x]=a[l[x]]+a[r[x]]-a[x];q.push(pa(a[x],x));49         a[l[x]]=a[r[x]]=inf;50         r[l[x]=l[l[x]]]=x;l[r[x]=r[r[x]]]=x;51     }52     cout<<ans<<endl;53     return 0;54 }