1 #include <bits/stdc++.h> 2 #define _for(i,a,b) for(int i = (a);i < b;i ++) 3 #define _rep(i,a,b) for(int i = (a);i > b;i --) 4 #define INF 0x3f3f3f3f 5 #define MOD 1000000007 6 #define pb push_back 7 #define maxn 500003 8 typedef long long ll; 9 using namespace std; 10 inline ll read() 11 { 12 ll ans = 0; 13 char ch = getchar(), last = ' '; 14 while(!isdigit(ch)) last = ch, ch = getchar(); 15 while(isdigit(ch)) ans = (ans << 1) + (ans << 3) + ch - '0', ch = getchar(); 16 if(last == '-') ans = -ans; 17 return ans; 18 } 19 inline void write(ll x) 20 { 21 if(x < 0) x = -x, putchar('-'); 22 if(x >= 10) write(x / 10); 23 putchar(x % 10 + '0'); 24 } 25 ll N,K; 26 struct Tree 27 { 28 ll id; 29 ll val; 30 }; 31 struct cmp 32 { 33 bool operator() (const Tree a,const Tree b) const 34 { 35 return a.val < b.val; 36 } 37 }; 38 priority_queue<Tree,vector<Tree>,cmp> pq; 39 ll a[maxn]; 40 ll l[maxn],r[maxn]; 41 ll vis[maxn]; 42 ll ans = 0; 43 int main() 44 { 45 N = read(); 46 K = read(); 47 _for(i,1,N+1) 48 { 49 a[i] = read(); 50 l[i] = i-1;r[i] = i+1; 51 pq.push({i,a[i]}); 52 } 53 54 _for(i,0,K) 55 { 56 Tree tmp = pq.top(); 57 while(vis[tmp.id]) 58 { 59 pq.pop(); 60 tmp = pq.top(); 61 } 62 if(tmp.val<=0) 63 break; 64 pq.pop(); 65 ans += tmp.val; 66 pq.push({tmp.id,a[l[tmp.id]]+a[r[tmp.id]]-tmp.val}); 67 a[tmp.id] = a[l[tmp.id]]+a[r[tmp.id]]-tmp.val; 68 vis[l[tmp.id]] = vis[r[tmp.id]] = 1; 69 l[tmp.id]=l[l[tmp.id]];r[l[tmp.id]]=tmp.id; 70 r[tmp.id]=r[r[tmp.id]];l[r[tmp.id]]=tmp.id; 71 } 72 write(ans); 73 return 0; 74 }