제출 #1117944

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
1117944		mingga	Building Bridges (CEOI17_building)	C++17	100 / 100	45 ms	19224 KiB

building

#include <bits/stdc++.h>
using namespace std;
 
#define ln '\n'
#define fi first
#define se second
#define pb push_back
#define all(x) (x).begin(), (x).end()
#define sz(x) (int)(x).size()
#define int long long
const int inf = 2e18;
const int N = 1e5 + 7;
const int M = 1e6 + 7;
int h[N], w[N], n, ps[N], f[N];

struct line {
    int a, b;
    line() {}
    line(int a, int b) : a(a), b(b) {}
    int calc(int x) {
        return a * x + b;
    }
    int slope() {
        return a;
    }
};

struct lichao {
    vector<line> st;
    lichao() {}
    int n;
    lichao(int n) : n(n) {
        st.resize(n + 1, line(0, inf));
    }
    void update(line f, int l, int r) {
        if(l > r) return ;
        int m = (l + r) >> 1;
        if(l == r) {
            st[m] = f.calc(l) < st[m].calc(l) ? f : st[m];
            return;
        }
        if(f.calc(m) < st[m].calc(m)) swap(f, st[m]);
        if(f.slope() > st[m].slope()) update(f, l, m - 1);
        if(f.slope() < st[m].slope()) update(f, m + 1, r);
    }
    int query(int l, int r, int x) {
        int m = (l + r) >> 1;
        int cur = st[m].calc(x);
        if(x == m) return cur;
        if(x < m) return min(cur, query(l, m - 1, x));
        return min(cur, query(m + 1, r, x));
    }
};

int a(int i) {
    return - 2 * h[i];
}
int b(int i) {
    return f[i] - ps[i] + h[i] * h[i];
}


signed main() {
    cin.tie(0) -> sync_with_stdio(0);
    cin >> n;
    for(int i = 1; i <= n; i++) cin >> h[i];
    for(int i = 1; i <= n; i++) cin >> w[i], ps[i] = ps[i - 1] + w[i];
    lichao st(M);
    st.update(line(a(1), b(1)), 0, M);
    for(int i = 2; i <= n; i++) {
        int ext = ps[i - 1] + h[i] * h[i];
        f[i] = st.query(0, M, h[i]) + ext;
        st.update(line(a(i), b(i)), 0, M);
    }
    cout << f[n];
}

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