Submission #973611

#	Time	Username	Problem	Language	Result	Execution time	Memory
973611		Ghetto	Building Bridges (CEOI17_building)	C++17	100 / 100	91 ms	18632 KiB

building

#include <bits/stdc++.h>
using namespace std;
using lint = long long;
using pll = pair<lint, lint>;
const int MAX_N = 1e5 + 5;
const lint MAX_H = 1e6 + 5, INF = 2e18;

int n;
lint h[MAX_N], w[MAX_N];

pll lct[60 * MAX_H];
int n_nodes, l_child[60 * MAX_H], r_child[60 * MAX_H];
void propogate(int u) {
    if (l_child[u]) return;
    n_nodes++, l_child[u] = n_nodes, lct[n_nodes] = {0, INF};
    n_nodes++, r_child[u] = n_nodes, lct[n_nodes] = {0, INF};
}
lint eval(pll x, lint y) {
    return x.first * y + x.second;
}
void update(pll x, int u = 1, lint lo = 0, lint hi = MAX_H) {
    lint mid = (lo + hi) / 2;
    if (eval(x, mid) < eval(lct[u], mid)) swap(x, lct[u]);
    if (lo == hi) return;
    propogate(u);
    if (eval(x, lo) < eval(lct[u], lo)) update(x, l_child[u], lo, mid);
    else update(x, r_child[u], mid + 1, hi);
}
lint query(lint i, int u = 1, lint lo = 0, lint hi = MAX_H) {
    if (i < lo || i > hi) return INF;
    if (lo == hi) return eval(lct[u], lo);
    propogate(u);
    lint mid = (lo + hi) / 2;
    return min({eval(lct[u], i), query(i, l_child[u], lo, mid), query(i, r_child[u], mid + 1, hi)});
}
void init() {
    n_nodes = 1;
    lct[1] = {0, INF};
}
lint dp[MAX_N];

int main() {
    cin >> n;
    for (int i = 1; i <= n; i++) cin >> h[i];
    for (int i = 1; i <= n; i++) cin >> w[i];

    init();
    dp[1] = -w[1];
    update({-2 * h[1], dp[1] + h[1] * h[1]});
    for (int i = 2; i <= n; i++) {
        dp[i] = query(h[i]) + h[i] * h[i] - w[i];
        update({-2 * h[i], dp[i] + h[i] * h[i]});
    }

    lint ans = dp[n];
    for (int i = 1; i <= n; i++) ans += w[i];
    cout << ans << '\n';
} 

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