Submission #974032

#	Time	Username	Problem	Language	Result	Execution time	Memory
974032		n3rm1n	Building Bridges (CEOI17_building)	C++17	0 / 100	25 ms	14124 KiB

building

#include<bits/stdc++.h>
#define endl '\n'
using namespace std;
const long long MAXN = 1e5 + 10, MAXX = 1e6+10;
void speed()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);
}
long long n, h[MAXN], w[MAXN];
long long pref[MAXN];
void read()
{
    cin >> n;
    for (long long i = 1; i <= n; ++ i)
        cin >> h[i];
    for (long long i = 1; i <= n; ++ i)
    {
        cin >> w[i];
        pref[i] = pref[i-1] + w[i];
    }
}
struct line
{
    long long k, m;
    line(){};
    line(long long _k, long long _m)
    {
        k = _k;
        m = _m;
    }
    long long calc(long long x)
    {
        return (x * k + m);
    }
};

struct li_chao
{
    line t[MAXX * 4];
    bool used[MAXX];
    void update(long long i, long long l, long long r, line curr)
    {
        if(l > r)return;
        if(!used[i])
        {
            t[i] = curr;
            used[i] = 1;
            return;
        }

        if(t[i].calc(l) < curr.calc(l))swap(t[i], curr);
        if(l == r)return;

        long long mid = (l + r) / 2;



        if(t[i].calc(mid) > curr.calc(mid))
            update(i * 2 + 1, mid + 1, r, curr);
        else
        {
            swap(t[i], curr);
            update(i * 2, l, mid, curr);
        }
    }


    long long query(long long i, long long l, long long r, long long x)
    {
        if(l > r)return 0;
        if(!used[i])return 0;
        if(l == r)return t[i].calc(x);

        long long mid = (l + r) / 2, res = t[i].calc(x);
        if(x <= mid)res = min(res, query(i * 2, l, mid, x));
        else res = min(res, query(i * 2 + 1, mid + 1, r, x));
        return res;
    }

};
li_chao li;
long long dp[MAXN];
void solve()
{
    dp[1] = 0;
    line neww = line(- 2 * h[1], h[1] * h[1] - pref[1]);

    //cout << "k = " << - 2 * h[1] << " m = " << h[1] * h[1] - pref[1] << endl;
    li.update(1, 1, 1e6, neww);
    for (long long i = 2; i <= n; ++ i)
    {

        dp[i] = li.query(1, 1, 1e6, h[i]) + h[i] * h[i] + pref[i-1];
       // cout << dp[i] << endl;

        neww = line(- 2*h[i], h[i] * h[i] - pref[i] + dp[i]);
       // cout << "k = " << - 2 * h[i] << " m = " << h[i] * h[i] - pref[i] + dp[i] << endl;
        li.update(1, 1, 1e6, neww);
    }
    cout << dp[n] << endl;
}
int main()
{
    speed();

    read();
    solve();
    return 0;
}

• Subtask 1: 0 / 30
• Subtask 2: 0 / 30
• Subtask 3: 0 / 40