蒟蒻线段树优化60pts求调

#include<bits/stdc++.h>
using namespace std;
int f[100010],a[100010],n,k,sum,ans=INT_MAX;
struct SegmentTree{
    int l,r,dat;
    #define l(p) t[p].l
    #define r(p) t[p].r
    #define dat(p) t[p].dat
}t[400010];
template<typename T> inline void read(T &x){
    x=0;
    char ch=getchar();
    bool fl=true;
    while(!isdigit(ch)){
        if(ch=='-') fl=!fl;
        ch=getchar();
    }
    while(isdigit(ch)){
        x=(x<<3)+(x<<1)+(ch^48);
        ch=getchar();
    }
    x=fl?x:-x;
}
template<typename T> inline void write(T x){
    if(x<0){
        putchar('-');
        x=-x;
    }
    if(x>9) write(x/10);
    putchar(x%10^48);
}
inline void build(int p,int l,int r){
    l(p)=l,r(p)=r;
    if(l==r){
        dat(p)=f[l];
        return;
    }
    int mid=(l+r)>>1;
    build(p<<1,l,mid);
    build(p<<1|1,mid+1,r);
    dat(p)=min(dat(p<<1),dat(p<<1|1));
}
inline void change(int p,int x,int v){
    if(l(p)==r(p)){
        dat(p)=v;
        return;
    }
    int mid=(l(p)+r(p))>>1;
    if(x<=mid) change(p<<1,x,v);
    else change(p<<1|1,x,v);
    dat(p)=min(dat(p<<1),dat(p<<1|1));
}
inline int ask(int p,int l,int r){
    if(l<=l(p)&&r>=r(p)) return dat(p);
    int mid=(l(p)+r(p))>>1,val=INT_MAX;
    if(l<=mid) val=min(val,ask(p<<1,l,r));
    if(r>mid) val=min(val,ask(p<<1|1,l,r));
    return val;
}
int main(){
    read(n);
    read(k);
    for(int i=1;i<=n;++i){
        read(a[i]);
        sum+=a[i];
    }
    for(int i=1;i<=k+1;++i)
        f[i]=a[i];
    build(1,1,n);
    for(int i=k+2;i<=n;++i){
        f[i]=ask(1,i-k-1,i-1)+a[i];
        change(1,i,f[i]);
    }
    for(int i=n-k;i<=n;++i)
        ans=min(ans,f[i]);
    write(sum-ans);
    putchar('\n');
    return 0;
}