Submission #641952

#	Time	Username	Problem	Language	Result	Execution time	Memory
641952		SirCovidThe19th	Building Bridges (CEOI17_building)	C++17	100 / 100	114 ms	9172 KiB

building

#include <bits/stdc++.h>
using namespace std;

template<class T> struct lichao{
    struct line{
        T m, b;
        T operator()(T x){ return m * x + b; }
    };
    lichao(){ extend(0); extend(0); }
    const T lim = 1e18; vector<line> seg; vector<int> lc, rc;
    
    int extend(int i){
        if (i) return i;
        seg.push_back({0, lim}); lc.push_back(0); rc.push_back(0);
        return seg.size() - 1;
    }
    void upd(line S, int l = -1e9, int r = 1e9, int i = 1){
        if (S.b == lim) return;
        if (l == r){ seg[i] = (S(l) < seg[i](l)) ? S : seg[i]; return; }
        if (seg[i].m > S.m) swap(seg[i], S); 

        int mid = (l + r) / 2 - (l + r < 0 and (l + r) % 2);
        if (S(mid) < seg[i](mid)){
            swap(S, seg[i]);
            upd(S, mid + 1, r, rc[i] = extend(rc[i]));
        }
        else upd(S, l, mid, lc[i] = extend(lc[i]));
    }
    T qry(int x, int l = -1e9, int r = 1e9, int i = 1){
        if (x < l or x > r or !i) return lim;
        if (l == r) return seg[i](l);
        int mid = (l + r) / 2 - (l + r < 0 and (l + r) % 2);
        return min({seg[i](x), qry(x, l, mid, lc[i]), qry(x, mid + 1, r, rc[i])});
    }
};

int n; long long H[100005], pref[100005], dp[100005]; lichao<long long> lc;

int main(){
    cin >> n;
    for (int i = 1; i <= n; i++) cin >> H[i];
    for (int i = 1; i <= n; i++) cin >> pref[i], pref[i] += pref[i - 1];

    for (int i = 1; i <= n; i++){
        dp[i] = lc.qry(H[i]) + (H[i] * H[i] + pref[i - 1]);
        if (i == 1) dp[i] = 0;
        lc.upd({-2 * H[i], H[i] * H[i] + dp[i] - pref[i]});
    }
    cout<<dp[n]<<"\n";
}

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