【动态规划】【单调队列】tyvj1305 最大子序和

#include<cstdio>
#include<deque>
#include<algorithm>
#include<iostream>
using namespace std;
typedef long long ll;
int n,m;
ll a[300100],ans;
deque<int>q;
int main(){
scanf("%d%d",&n,&m);
for(int i=1;i<=n;++i){
cin>>a[i];
}
for(int i=2;i<=n;++i){
a[i]+=a[i-1];
}
q.push_front(0);
for(int i=1;i<=n;++i){
while((!q.empty()) && a[q.front()]>=a[i]){
q.pop_front();
}
q.push_front(i);
while(q.back()<i-m){
q.pop_back();
}
ans=max(ans,a[i]-a[q.back()]);
}
cout<<ans<<endl;
return 0;
}