Submission #1264744

#	Time	Username	Problem	Language	Result	Execution time	Memory
1264744		minhpk	Building Bridges (CEOI17_building)	C++20	100 / 100	62 ms	65352 KiB

building

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

struct Line {
    long long a, b;
    
    Line() : a(0), b(LLONG_MAX) {}
    Line(long long a, long long b) : a(a), b(b) {}
    
    long long calc(long long x) {
        return a * x + b;
    }
};

struct LiChao {
    vector<Line> lc;
    
    void init(int n) {
        lc.resize(n * 4, Line());
    }
    
    void upd(int id, int l, int r, Line L) {
        int mid = (l + r) >> 1;
        bool left = L.calc(l) < lc[id].calc(l);
        bool m = L.calc(mid) < lc[id].calc(mid);
        if (m) {
            swap(lc[id], L);
        }
        if (l == r) return;
        if (left != m) {
            upd(id * 2, l, mid, L);
        } else {
            upd(id * 2 + 1, mid + 1, r, L);
        }
    }
    
    long long get(int id, int l, int r, int x) {
        if (l == r) {
            return lc[id].calc(x);
        }
        int mid = (l + r) >> 1;
        if (x <= mid) {
            return min(lc[id].calc(x), get(id * 2, l, mid, x));
        }
        return min(lc[id].calc(x), get(id * 2 + 1, mid + 1, r, x));
    }
};

const int MAXN = 1e6 + 5;
LiChao T;
long long h[MAXN], w[MAXN];
long long dp[MAXN];

long long p1(int x) {
    return -2 * h[x];
}

long long p2(int x) {
    return dp[x] + h[x] * h[x] - w[x];
}

long long p3(int x) {
    return h[x] * h[x] + w[x - 1];
}

void solve() {
    int n;
    cin >> n;
    for (int i = 1; i <= n; i++) {
        cin >> h[i];
    }
    for (int i = 1; i <= n; i++) {
        cin >> w[i];
        w[i] += w[i - 1];
    }
    T.init(MAXN + 1);
    dp[1] = 0;
    T.upd(1, 0, MAXN, {p1(1), p2(1)});
    for (int i = 2; i <= n; i++) {
        dp[i] = T.get(1, 0, MAXN, h[i]) + p3(i);
        T.upd(1, 0, MAXN, {p1(i), p2(i)});
    }
    cout << dp[n];
}

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

    int t = 1;
    while (t--) {
        solve();
    }
    return 0;
}

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