征途

#include<cstdio>
#include<queue>
#include<cstring>
using namespace std;
const int maxn=5e5+10;
typedef long long ll;
ll a[maxn],b[maxn],sum[maxn],f[maxn];
struct Node{
    int id;
    ll w;
    Node(){};
    Node(int x,ll y){
        id=x;
        w=y;
    }
    bool operator<(const Node &a)const{
        return w>a.w;
    }
};
priority_queue<Node> q1;
priority_queue<Node> q2;
int main(){
    freopen("empire.in","r",stdin);
    freopen("empire.out","w",stdout);
    int n,k;
    scanf("%d%d",&n,&k);    
    for(int i=1;i<=n;++i) scanf("%lld",&a[i]);
    for(int i=0;i<n;++i) scanf("%lld",&b[i]);
    for(int i=1;i<=n;++i) sum[i]=sum[i-1]+a[i];
    memset(f,0x3f,sizeof(f));
    f[0]=0;
    q1.push(Node(0,f[0]+b[0]));
    ll s;
    for(int i=1;i<=n;++i){
        while(!q1.empty()&&i-q1.top().id>k) q1.pop();    
        while(!q1.empty()&&q1.top().w<(s=f[q1.top().id]+sum[i]-sum[q1.top().id])){
            q2.push(Node(q1.top().id,s-sum[i]));
            q1.pop();
        }
        while(!q2.empty()&&i-q2.top().id>k) q2.pop();
        if(!q1.empty()) f[i]=min(f[i],q1.top().w);
        if(!q2.empty()) f[i]=min(f[i],q2.top().w+sum[i]);
        q1.push(Node(i,f[i]+b[i]));
    }
    printf("%lld\n",f[n]);
    return 0;    
}