Submission #477335

#	Time	Username	Problem	Language	Result	Execution time	Memory
477335		XBoRickie	Building Bridges (CEOI17_building)	C++11	100 / 100	315 ms	9488 KiB

building

#include <bits/stdc++.h>
using namespace std;
// Typedef
typedef long double                ld;
typedef long long int              int64;
typedef unsigned long long int     uint64;
typedef std::pair<int, int>        PLL;
typedef std::pair<int64, int64>    PII;
typedef std::vector<int>           VI;
typedef std::vector<long long>     VLL;
// Define For-loop
#define FOR(i, j, k, in)           for (int i = (j); i < (k) ; i += (in))
#define FORW(i, j, k, in)          for (int i = (j); i <= (k); i += (in))
#define RFOR(i, j, k, in)          for (int i = (j); i >= (k); i -= (in))
// Define Data structure func
#define all(cont)                  cont.begin(), cont.end()
#define rall(cont)                 cont.rbegin(), cont.rend()
#define sz(cont)                   int((cont).size())
#define pb                         push_back
#define mp                         make_pair
#define fi                         first
#define se                         second
// Define number
#define IINF                       0x3f3f3f3f
#define LLINF                      1000111000111000111LL
#define PI                         3.1415926535897932384626433832795
// Other
#define elif                       else if
#define lend                       '\n'
#define hardio(name)               freopen(name".inp","r",stdin), freopen(name".out","w",stdout);
void FastIO() { std::ios_base::sync_with_stdio(false); std::cin.tie(NULL);  }

const int MOD = 1e9 + 7, MOD2 = 1e9 + 9;
// ======================================================================

int64 h[100006], pf[100006] = {};
int64 dp[100006] = {};
int sqN = 0, n;

struct CVH {
    vector<PII> lines;
    double intersect(PII& l, PII& r) {
        return (1.0*(l.se - r.se))/(1.0*(r.fi - l.fi));
    }
    bool bad(PII& a, PII& b, PII& c) {
        return intersect(a, c) <= intersect(b, a);
    }
    void addLine(PII line, bool flag) {
        if (flag) {
            while (sz(lines) >= 2 && bad(lines[sz(lines) - 2], lines[sz(lines) - 1], line)) lines.pop_back();
            if (sz(lines) == 1 && lines[0].fi == line.fi) lines.pop_back();
            lines.pb(line);
        } else {
            lines.pb(line);
            RFOR(i, sz(lines) - 1, 1, 1) {
                if (lines[i - 1] <= lines[i]) swap(lines[i - 1], lines[i]);
                else break;
            }
        }
    }
    int64 query(int64 x) {
        int l = 0, r = sz(lines) - 1, m, best = -1;
        while (l <= r) {
            m = (l + r) >> 1;
            double pos = m > 0 ? intersect(lines[m], lines[m - 1]) : -IINF;
            if (pos <= x) best = m, l = m + 1;
            else r = m - 1;
        }
        return best == -1 ? IINF : lines[best].fi * x + lines[best].se;
    }
} off, aux, pil;

void Clear_Stack() {
    aux.lines.clear();
    int esq = 0, dir = 0;
    while(esq < sz(off.lines) && dir < sz(pil.lines)) {
        if(off.lines[esq] >= pil.lines[dir]) aux.addLine(off.lines[esq], 1), ++esq;
        else aux.addLine(pil.lines[dir], 1), dir++;
    }
    while(esq < sz(off.lines)) aux.addLine(off.lines[esq], 1), ++esq;
    while(dir < sz(pil.lines)) aux.addLine(pil.lines[dir], 1), ++dir;
    off.lines = aux.lines, pil.lines.clear(), aux.lines.clear();
}

int main(int argc, char* argv[]) {
    FastIO();

    cin >> n; sqN = sqrt(n);
    FORW(i, 1, n, 1) cin >> h[i];
    FORW(i, 1, n, 1) cin >> pf[i], pf[i] += pf[i - 1];

    dp[1] = 0;
    pil.addLine(PII(-2ll * h[1], 1ll * h[1] * h[1] - pf[1]), 0);

    FORW(i, 2, n, 1) {
        int64 x = off.query(h[i]);
        for(auto& u : pil.lines) x = min(x, u.fi * h[i] + u.se);
        dp[i] = x + h[i] * h[i] + pf[i - 1];
        pil.addLine(PII(-2ll * h[i], 1ll * h[i] * h[i] - pf[i] + dp[i]), 0);
        if (sz(pil.lines) >= sqN) Clear_Stack();
    }

    cout << dp[n] << endl;


    return 0; }

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