Submission #934280

#	Time	Username	Problem	Language	Result	Execution time	Memory
934280		mnasser02	Building Bridges (CEOI17_building)	C++17	100 / 100	39 ms	9812 KiB

building

#include <bits/stdc++.h>

#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

using namespace std;
using namespace __gnu_pbds;

typedef long long ll;
typedef long double ld;
typedef pair<int, int> ii;
typedef vector<int> vi;
typedef tuple<int, int, int> iii;
typedef pair<ll, ll> pll;
typedef vector<ii> vii;
typedef vector<ll> vll;
typedef tree<int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update> os_tree;
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define LSOne(S) ((S) & -(S))

template <class T>
bool ckmin(T &a, const T &b) { return b < a ? a = b, 1 : 0; }
template <class T>
bool ckmax(T &a, const T &b) { return a < b ? a = b, 1 : 0; }

struct Line {
    mutable ll k, m, p;
    bool operator<(const Line &o) const { return k < o.k; }
    bool operator<(ll x) const { return p < x; }
};

struct LineContainer : multiset<Line, less<>> {
    // (for doubles, use inf = 1/.0, div(a,b) = a/b)
    static const ll inf = LLONG_MAX;
    ll div(ll a, ll b) {  // floored division
        return a / b - ((a ^ b) < 0 && a % b);
    }
    bool isect(iterator x, iterator y) {
        if (y == end()) return x->p = inf, 0;
        if (x->k == y->k)
            x->p = x->m > y->m ? inf : -inf;
        else
            x->p = div(y->m - x->m, x->k - y->k);
        return x->p >= y->p;
    }
    void add(ll k, ll m) {
        auto z = insert({k, m, 0}), y = z++, x = y;
        while (isect(y, z)) z = erase(z);
        if (x != begin() && isect(--x, y)) isect(x, y = erase(y));
        while ((y = x) != begin() && (--x)->p >= y->p)
            isect(x, erase(y));
    }
    ll query(ll x) {
        assert(!empty());
        auto l = *lower_bound(x);
        return l.k * x + l.m;
    }
};

void solve() {
    int n;
    cin >> n;

    vi h(n), w(n);
    vll pre(n + 1);
    for (int i = 0; i < n; i++) {
        cin >> h[i];
    }
    for (int i = 0; i < n; i++) {
        cin >> w[i];
        pre[i + 1] = pre[i] + w[i];
    }

    vll dp(n);
    LineContainer lc;

    lc.add(2 * h[0], pre[1] - (ll)h[0] * h[0]);
    for (int i = 1; i < n; i++) {
        ll y = -lc.query(h[i]);
        dp[i] = y + (ll)h[i] * h[i] + pre[i];
        lc.add(2 * h[i], pre[i + 1] - (ll)h[i] * h[i] - dp[i]);
    }
    cout << dp[n - 1] << "\n";
}

int main() {
    ios_base::sync_with_stdio(0), cin.tie(0);

    int tc = 1;
    // cin >> tc;

    while (tc--) {
        solve();
    }
    return 0;
}

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