[BZOJ3437]小P的牧场

来源：互联网发布：本地服务器域名绑定编辑：程序博客网时间：2024/05/01 06:42

原题地址

同BZOJ1096…

AC code:

#include <cstdio>#include <queue>using namespace std;typedef long long ll;const ll N=1000010;const ll INF=(1<<29)*(1<<29);ll n;ll a[N],b[N],s[N],t[N],f[N];struct Vec{    ll x,y;    Vec() {}    Vec(ll x,ll y):x(x),y(y) {}    friend Vec operator-(Vec a,Vec b){        return Vec(a.x-b.x,a.y-b.y);    }    friend ll operator*(Vec a,Vec b){        return a.x*b.y-a.y*b.x;    }};deque<Vec> Q;int main(){    scanf("%lld",&n);    for(ll i=1;i<=n;i++) scanf("%lld",&a[i]);    for(ll i=1;i<=n;i++) scanf("%lld",&b[i]);    for(ll i=1;i<=n;i++) s[i]=s[i-1]+b[i];    for(ll i=1;i<=n;i++) t[i]=t[i-1]+s[i-1];    for(ll i=1;i<=n;i++){        ll  A=-i;        Vec tmp=Vec(s[i-1],f[i-1]-t[i-1]+(i-1)*s[i-1]);        while(Q.size()>1){            Vec a,b;            a=Q.front();Q.pop_front();b=Q.front();            if((tmp-a)*(a-b)<0){                Q.push_front(a);                break;            }        }        Q.push_front(tmp);        while(Q.size()>1){            Vec a,b;            a=Q.back();Q.pop_back();b=Q.back();            if(A*a.x+a.y<A*b.x+b.y){                Q.push_back(a);                f[i]=A*a.x+a.y;                break;            }            f[i]=A*b.x+b.y;        }        f[i]+=a[i]+t[i];    }    printf("%lld\n",f[n]);    return 0;}

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