Submission #868263

#	Time	Username	Problem	Language	Result	Execution time	Memory
868263		lalala56	Building Bridges (CEOI17_building)	C++17	0 / 100	29 ms	2652 KiB

building

#include<bits/stdc++.h>
using namespace std;
#define PROB "BRIDGEPOL"
#define ll long long
#define ull unsigned long long
#define FOR(i,a,b) for(int i=a;i<=b;(i)++)
#define FOD(i,a,b) for(int i=a;i>=b;(i)--)
#define pii pair<int,int>
#define pll pair<ll,ll>
#define pil pair<int,ll>
#define pli pair<ll,int>
#define fi first
#define se second
#define mp make_pair
#define SZ(x) int(x.size())
#define bit(p,i) ((p>>i)&1)


template <class T>
inline bool minimize(T &x, const T &y){ if (x > y){x = y; return 1;} return 0; }

template <class T>
inline bool maximize(T &x, const T &y){ if (x < y){x = y; return 1;} return 0; }
const int N=1e5+9;
ll f[N],h[N],w[N];
int n;

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 get(ll x) {
		//assert(!empty());
		auto l = *lower_bound(x);
		return l.k * x + l.m;
	}
};
void giai(){
    cin>>n;
    FOR(i,1,n)cin>>h[i];
    FOR(i,1,n){
        int x;cin>>x;
        w[i]=w[i-1]+x;
    }
    LineContainer c;
    c.add(-h[1],-h[1]*h[1]);
    FOR(i,2,n){
        f[i]=h[i]*h[i]+w[i-1]-c.get(-2*h[i]);
        c.add(-h[i],-(h[i]*h[i]-w[i]+f[i]));
        //cout<<h[i]*h[i]+w[i-1]<<" "<<f[i]<<'\n';
    }
    cout<<'\n';
    cout<<f[n];

}
int main(){
    if(fopen(PROB".inp","r")){
        freopen(PROB".inp","r",stdin);
        freopen(PROB".out","w",stdout);
    }
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    giai();
}

Compilation message (stderr)

building.cpp: In function 'int main()':
building.cpp:78:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   78 |         freopen(PROB".inp","r",stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
building.cpp:79:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   79 |         freopen(PROB".out","w",stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~

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