제출 #1325779

#제출 시각아이디문제언어결과실행 시간메모리
1325779sh_qaxxorov_571Building Bridges (CEOI17_building)C++20
100 / 100
37 ms7132 KiB
#include <iostream>
#include <vector>
#include <algorithm>

using namespace std;

typedef long long ll;

const ll INF = 1e18;
const int MAXH = 1000005;

struct Line {
    ll m, b;
    ll eval(ll x) { return m * x + b; }
};

Line tree[4 * MAXH];
bool has_line[4 * MAXH];

void add_line(int node, int l, int r, Line nw) {
    if (!has_line[node]) {
        tree[node] = nw;
        has_line[node] = true;
        return;
    }
    int mid = (l + r) / 2;
    bool left_better = nw.eval(l) < tree[node].eval(l);
    bool mid_better = nw.eval(mid) < tree[node].eval(mid);

    if (mid_better) swap(tree[node], nw);

    if (l == r) return;
    if (left_better != mid_better) add_line(2 * node, l, mid, nw);
    else add_line(2 * node + 1, mid + 1, r, nw);
}

ll query(int node, int l, int r, int x) {
    if (!has_line[node]) return INF;
    ll res = tree[node].eval(x);
    if (l == r) return res;
    int mid = (l + r) / 2;
    if (x <= mid) res = min(res, query(2 * node, l, mid, x));
    else res = min(res, query(2 * node + 1, mid + 1, r, x));
    return res;
}

int main() {
    ios::sync_with_stdio(false); cin.tie(0);

    int n; cin >> n;
    vector<ll> h(n + 1), w(n + 1), s(n + 1, 0);
    for (int i = 1; i <= n; i++) cin >> h[i];
    for (int i = 1; i <= n; i++) {
        cin >> w[i];
        s[i] = s[i - 1] + w[i];
    }

    vector<ll> dp(n + 1);
    dp[1] = 0;
    add_line(1, 0, MAXH, {-2 * h[1], dp[1] + h[1] * h[1] - s[1]});

    for (int i = 2; i <= n; i++) {
        dp[i] = h[i] * h[i] + s[i - 1] + query(1, 0, MAXH, h[i]);
        add_line(1, 0, MAXH, {-2 * h[i], dp[i] + h[i] * h[i] - s[i]});
    }

    cout << dp[n] << endl;

    return 0;
}
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