제출 #923796

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
923796		Karoot	Building Bridges (CEOI17_building)	C++17	100 / 100	38 ms	11792 KiB

building

#include <iostream>
#include <cmath>
#include <unordered_map>
#include <map>
#include <set>
#include <queue>
#include <vector>
#include <string>
#include <iomanip>
#include <algorithm>
#include <climits>

#define all(x)  (x).begin(), (x).end()
#define rall(x)  (x).rbegin(), (x).rend()

using namespace std;

typedef long long ll;

ll linf = 1e15+1;

inline void scoobydoobydoo(){
    ios::sync_with_stdio(false);
    ios_base::sync_with_stdio(false);
    cin.tie(NULL); cout.tie(NULL);
}

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) {
		if (empty())return -linf;
		auto l = *lower_bound(x);
		return l.k * x + l.m;
	}
};

LineContainer LC;

const int MAXN = 2e5+1;

ll mem[MAXN];
ll pref[MAXN];
ll heights[MAXN];
int n;

ll dp(){
    mem[0] = 0;
    LC.add(2*heights[0], -pow(heights[0],2)+pref[0]);
    //cout << mem[0] << " ";
    for (int i = 1; i < n; i++){
        mem[i] = pref[i-1]+pow(heights[i], 2)-LC.query(heights[i]);
        //cout << mem[i] << " ";
        LC.add(2*heights[i], -mem[i]-pow(heights[i], 2)+pref[i]);
    }
    //cout << endl;
    return mem[n-1];
}

int main(){
    scoobydoobydoo();
    cin >> n;
    for (int i = 0; i < n; i++) cin >> heights[i];
    for (int i = 0; i < n; i++){
        cin >> pref[i];
        pref[i] += (i == 0 ? 0 : pref[i-1]);
    }

    cout << dp() << endl;


    return 0;
}

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