Submission #988385

#	Time	Username	Problem	Language	Result	Execution time	Memory
988385		VMaksimoski008	Building Bridges (CEOI17_building)	C++17	0 / 100	93 ms	66028 KiB

building

#include <bits/stdc++.h>

#define sz(x) (int)x.size()
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
//#define int long long

using namespace std;

using ll = long long;
using ull = unsigned long long;
using ld = long double;
using pii = pair<int, int>;
using pll = pair<ll, ll>;

const int mod = 1e9 + 7;
const int LOG = 20;
const int maxn = 1e6 + 5;
const double eps = 1e-9;

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

struct LiChao {
    int n;
    vector<Line> tree;

    LiChao(int _n) {
        n = _n;
        tree.resize(4*_n+5);
        for(Line &l : tree) l = { (ll)2e12, (ll)1e18 };
    }

    void insert(int u, int tl, int tr, Line seg) {
        if(tl + 1 == tr) {
            if(seg(tl) < tree[u](tl)) tree[u] = seg;
            return ;
        }

        int tm = (tl + tr) / 2;
        if(tree[u].m < seg.m) swap(tree[u], seg);
        if(tree[u](tm) > seg(tm)) {
            swap(tree[u], seg);
            insert(2*u+1, tl, tm, seg);
        } else insert(2*u+2, tm, tr, seg);
    }

    ll query(int u, int tl, int tr, ll p) {
        if(tl + 1 == tr) return tree[u](p);
        int tm = (tl + tr) / 2;
        if(p < tm) return min(tree[u](p), query(2*u+1, tl, tm, p));
        return min(tree[u](p), query(2*u+1, tm, tr, p));
    }

    void insert(Line seg) { insert(1, 0, n, seg); }
    ll query(ll p) { return query(1, 0, n, p); }
};

int32_t main() {
    int n;
    cin >> n;

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

    vector<ll> dp(n+1, 1e18);
    LiChao cht(maxn+5);
    //(h[i] - h[j]) * (h[i] - h[j]) = h[i]^2 - 2 * h[i] * h[j] + h[j]
    // dp[i] = min(dp[i], dp[j] + h[i] * h[i] - 2 * h[i] * h[j] + h[j] * h[j] + pref[i] - pref[j] - w[i]);
    // dp[i] = min(dp[i], (h[i] * h[i] + pref[i] - w[i]) - 2 * h[i] * h[j] + h[j] * h[j] + dp[j] - pref[j] );
    for(int i=1; i<=n; i++) {
        // for(int j=1; j<i; j++) {
        //     dp[i] = min(dp[i], (h[i] * h[i] + pref[i] - w[i]) - 2 * h[i] * h[j] + h[j] * h[j] + dp[j] - pref[j] );
        // }
        if(i > 1) dp[i] = cht.query(h[i]) + h[i] * h[i] + pref[i] - w[i];
        else dp[i] = 0;
        cht.insert({ -2 * h[i], h[i] * h[i] + dp[i] - pref[i] });
    }

    cout << dp[n] << '\n';
    return 0;
}

• Subtask 1: 0 / 30
• Subtask 2: 0 / 30
• Subtask 3: 0 / 40