@[Donotplaygame](/user/549499)
把第16行移到for循环后面，是求完以后再更新。
第17行是 `dp[i - 1] - sum[i]`
```cpp
#include<bits/stdc++.h>
#define ll long long
using namespace std;
const int N=1000005;
ll n,k,a[N],sum[N],dp[N],p[N];
deque<ll>q;
int main()
{
ios::sync_with_stdio(0),cin.tie(0),cout.tie(0);
cin>>n>>k;
for(int i=1;i<=n;i++)cin>>a[i];
for(int i=1;i<=n;i++)sum[i]=sum[i-1]+a[i];
q.push_back(0);
for(int i=1;i<=n;i++)
{
p[i]=dp[i - 1]-sum[i];
while(q.size()&&p[q.back()]<=p[i])q.pop_back();
q.push_back(i);
while(q.size()&&i-q.front()>k)q.pop_front();
dp[i]=sum[i]+p[q.front()];
//for(int j=0;j<q.size();j++)cout<<q[j]<<" ";
//cout<<endl;
}
cout<<dp[n];
return 0;
}
```
by 蔡竣凯 @ 2022-10-02 11:58:06
@[蔡竣凯](/user/341036) 谢谢大佬%%%（$\color{white}\text{同校的}$
by Disjoint_cat @ 2022-10-02 12:04:50