Submission #908101

#	Time	Username	Problem	Language	Result	Execution time	Memory
908101		wii	Building Bridges (CEOI17_building)	C++17	100 / 100	42 ms	15952 KiB

building

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

typedef double db;
typedef long long ll;
typedef long double ld;

#define int ll
typedef pair<int, int> pii;

#define lx (id << 1)
#define rx (lx | 1)
#define gcd __gcd
#define pb push_back
#define all(x) (x).begin(), (x).end()
#define bit(i, mask) ((mask) >> (i) & 1)
#define reset(x, val) memset(x, val, sizeof(x))
#define foru(i,a,b) for(int i = (a); i <= (b); ++i)
#define ford(i,a,b) for(int i = (a); i >= (b); --i)
#define FastIO ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);

template<typename T> bool maximize(T &res, const T &val) { if (res < val) { res = val; return true; } return false; }
template<typename T> bool minimize(T &res, const T &val) { if (val < res) { res = val; return true; } return false; }

const ll Linf = 0x3f3f3f3f3f3f3f3f;
const int Inf = 0x3f3f3f3f;
const ll Mod = 1e9 + 7;
const ll Mod2 = ll(1e9) + 9;
const int Lim = 1e6 + 5;
const int inv6 = 166666668;

// #define Sieve
#ifdef Sieve
    vector<int> pr;
    vector<int> lpf;
    void Linear_sieve(int n = Lim) {
        pr.assign(1, 2);
        lpf.assign(n + 1, 2);

        for (int x = 3; x <= n; x += 2) {
            if (lpf[x] == 2) pr.push_back(lpf[x] = x);
            for (int i = 1; i < pr.size() && pr[i] <= lpf[x] && pr[i] * x <= n; ++i)
                lpf[pr[i] * x] = pr[i];
        }
    }
#endif

// #define Ckn_calc
#ifdef Ckn_calc
    const int LIM = 1e6 + 16;

    int fact[LIM + 10]; /// factorial:         fact[n] = n!
    int invs[LIM + 10]; /// inverse modular:   invs[n] = n^(-1)
    int tcaf[LIM + 10]; /// inverse factorial: tcaf[n] = (n!)^(-1)
    void precal_nck(int n = LIM)
    {
        fact[0] = fact[1] = 1;
        invs[0] = invs[1] = 1;
        tcaf[0] = tcaf[1] = 1;
        for (int i = 2; i <= n; ++i)
        {
            fact[i] = (1LL * fact[i - 1] * i) % Mod;
            invs[i] = Mod - 1LL * (Mod / i) * invs[Mod % i] % Mod;
            tcaf[i] = (1LL * tcaf[i - 1] * invs[i]) % Mod;
        }
    }

    ll C(int n, int k) {
        if (n < k || k < 0) return 0;

        ll res = fact[n];
        res *= tcaf[k], res %= Mod;
        res *= tcaf[n - k], res %= Mod;
        return res;
    }

    ll P(int n, int k) {
        ll res = fact[n];
        res *= tcaf[n - k], res %= Mod;
        return res;
    }
#endif

/// ====*====*====*====*====*====*====*====*====*====*====*====*====*====*====*====*====

const int base = 3;
const int N = 1e6 + 5;
const int K = log2(N) + 1;
const int dx[] = {+1, -1, 0, 0};
const int dy[] = {0, 0, +1, -1};
const int block_size = sqrt(2e9) + 2;

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;
	}
};

int n;
int a[N];
int w[N];
int dp[N];

void solve() {
	cin >> n;
	foru(i, 1, n) cin >> a[i];
	foru(i, 1, n) cin >> w[i];

	foru(i, 1, n) w[i] += w[i - 1];

	LineContainer cht;
	foru(i, 2, n) {
		int j = i - 1;
		cht.add(2LL * a[j], -(a[j] * a[j] + dp[j] - w[j]));
		dp[i] = -cht.query(a[i]) + a[i] * a[i] + w[i - 1];
	}

	cout << dp[n];
}

signed main() {
    FastIO;

    #define task "test"
    if (fopen(task".inp", "r")) {
		freopen(task".inp", "r", stdin);
		freopen(task".out", "w", stdout);
	}

    #ifdef Sieve
        Linear_sieve();
    #endif

    #ifdef Ckn_calc
        precal_nck();
    #endif

    int ntest = 1;
    // cin >> ntest;
    while (ntest--) {
        //cout << "Case " << q << ": " << "\n"; 
        solve();
        cout << "\n";
    }

    return 0;
}

/**  /\_/\
 *  (= ._.)
 *  / >TL \>AC
**/

Compilation message (stderr)

building.cpp: In function 'int main()':
building.cpp:155:10: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  155 |   freopen(task".inp", "r", stdin);
      |   ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
building.cpp:156:10: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  156 |   freopen(task".out", "w", stdout);
      |   ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

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