Submission #945739

#	Time	Username	Problem	Language	Result	Execution time	Memory
945739		12345678	Building Bridges (CEOI17_building)	C++17	100 / 100	41 ms	7516 KiB

building

#include <bits/stdc++.h>

using namespace std;

const int nx=1e5+5;

#define ll long long

ll n, h[nx], sm, w[nx];

struct line
{
    ll m, c;
    line(ll m, ll c): m(m), c(c){}
    ll val(ll x) {return m*x+c;}
};

struct lichaotree
{
    struct node
    {
        line a;
        node *l, *r;
        node(line a):a(a), l(0), r(0) {}
    };
    typedef node* pnode;
    pnode rt;
    void update(int l, int r, pnode &t, line nw)
    {
        if (!t) return t=new node(nw), void();
        int md=(l+r)/2;
        int ls=nw.val(l)<t->a.val(l);
        int ms=nw.val(md)<t->a.val(md);
        int rs=nw.val(r)<t->a.val(r);
        if (ms) swap(t->a, nw);
        if (l==r) return;
        if (ls^ms) update(l, md, t->l, nw);
        if (ms^rs) update(md+1, r, t->r, nw);
    }
    ll query(int l, int r, pnode t, int x)
    {
        if (!t) return LLONG_MAX;
        if (l==r) return t->a.val(x);
        int md=(l+r)/2;
        if (x<=md) return min(t->a.val(x), query(l, md, t->l, x));
        else return min(t->a.val(x), query(md+1, r, t->r, x));
    }
} s;

int main()
{
    cin.tie(NULL)->sync_with_stdio(false);
    cin>>n;
    for (int i=1; i<=n; i++) cin>>h[i];
    for (int i=1; i<=n; i++) cin>>w[i], sm+=w[i];
    s.update(0, 1e6, s.rt, line(-2*h[1], h[1]*h[1]-w[1]));
    //c.add(-2*h[1], h[1]*h[1]-w[1]);
    for (int i=2; i<=n-1; i++)
    {
        ll tmp=s.query(0, 1e6, s.rt, h[i])+h[i]*h[i]-w[i];
        //cout<<i<<' '<<tmp<<'\n';
        //ll tmp=c.query(h[i])+h[i]*h[i]-w[i];
        s.update(0, 1e6, s.rt, line(-2*h[i], h[i]*h[i]+tmp));
        //c.add(-2*h[i], tmp+h[i]*h[i]);
    }
    cout<<s.query(0, 1e6, s.rt, h[n])+h[n]*h[n]-w[n]+sm;
    //cout<<c.query(h[n])+h[n]*h[n]-w[n]+sm;
}

• Subtask 1: 30 / 30
• Subtask 2: 30 / 30
• Subtask 3: 40 / 40