Submission #46486

#	Time	Username	Problem	Language	Result	Execution time	Memory
46486		RockyB	Building Bridges (CEOI17_building)	C++17	30 / 100	3036 ms	4268 KiB

building

/// In The Name Of God

#pragma GCC optimize("Ofast")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")

#include <bits/stdc++.h>

#define f first
#define s second

#define pb push_back
#define pp pop_back
#define mp make_pair

#define sz(x) (int)x.size()
#define sqr(x) ((x) * 1ll * (x))
#define all(x) x.begin(), x.end()

#define Kazakhstan ios_base :: sync_with_stdio(0), cin.tie(0), cout.tie(0);

#define nl '\n'
#define ioi exit(0);

typedef long long ll;
typedef long double ld;
typedef unsigned long long ull;

const int N = (int)1e5 + 7;
const int K = 317;
const int inf = (int)1e9 + 7;
const int mod = (int)1e9 + 7;
const ll linf = (ll)1e18 + 7;

const int dx[] = {-1, 0, 1, 0, 1, -1, -1, 1};
const int dy[] = {0, 1, 0, -1, 1, -1, 1, -1};

using namespace std;

int n;
int h[N], w[N];
ll dp[N], s[N];

struct line {
	ll k, b;
	ll get(ll x) {
		return k * x + b;
	}
	bool operator < (const line &x) const {
		if (k != x.k) return k < x.k;
		return b < x.b;
	}
};

double inter(line a, line b) {
	return (b.b - a.b) / (a.k - b.k);
}
struct cht {
	vector <line> a, b;
	void build() {
		for (auto it : b) a.pb(it);
		b.clear();
		sort(all(a));
		vector <line> nw;
		for (auto it : a) {
			if (sz(nw) && nw.back().k == it.k) continue;
			while (sz(nw) > 1 && inter(it, nw.back()) <= inter(it, nw[sz(nw) - 2])) nw.pp();
			nw.pb(it);
		}
	}
	ll get(ll x) {
		int l = 0, r = sz(a) - 2, res = 0;
		while (l <= r) {
			int mid = l + r >> 1;
			if (a[mid].get(x) >= a[mid + 1].get(x)) res = mid + 1, l = mid + 1;
			else r = mid - 1;
		}
		ll ans = sz(a) ? a[res].get(x) : linf;
		//ll ans = linf;

		for (auto it : b) {
			ans = min(ans, it.get(x));
		}
		return ans;
	}
	void add(line x) {
		b.pb(x);
		//if (sz(b) >= K) build();
	}
} t;

int main() {
	#ifdef IOI2018
		freopen ("in.txt", "r", stdin);
	#endif
	Kazakhstan
	cin >> n;
	for (int i = 1; i <= n; i++) {
		cin >> h[i];
	}
	for (int i = 1; i <= n; i++) {
		cin >> w[i];
		s[i] = s[i - 1] + w[i];
	}
	memset(dp, 0x3f, sizeof(dp));
	dp[1] = 0;
	t.add({h[1], sqr(h[1]) + dp[1] - s[1]});
	for (int i = 2; i <= n; i++) {
		dp[i] = t.get(-2 * h[i]) + sqr(h[i]) + s[i - 1];
		t.add({h[i], sqr(h[i]) + dp[i] - s[i]});
		/*ll add = 0;
		for (int j = i - 1; j >= 1; j--) {
			dp[i] = min(dp[i], sqr(h[i] - h[j]) + (s[i - 1] - s[j]) + dp[j]);
			add += w[j];
		}*/
	}
	cout << dp[n];
	ioi
}

Compilation message (stderr)

building.cpp: In member function 'll cht::get(ll)':
building.cpp:73:16: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
    int mid = l + r >> 1;
              ~~^~~

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