最大子序和II

#include<iostream>
#include<queue>
#include<algorithm>
#include<limits.h>
using namespace std;
const int N=300010;
typedef long long LL;
LL s[N];
int n,m;
deque<int>q;

int main(void){
    cin>>n>>m;
    for(int i=1;i<=n;i++){
        cin>>s[i];
        s[i]+=s[i-1];
    }
    q.push_front(0);
    LL res=INT_MIN;
    for(int i=1;i<=n;i++){
        if(i-q.front()>m)q.pop_front();
        res=max(res,s[i]-s[q.front()]);
        while(q.size()&&s[q.back()]>=s[i])q.pop_back();
        q.push_back(i);
    }
    cout<<res<<endl;
    return 0;
}