Submission #723513

#	Time	Username	Problem	Language	Result	Execution time	Memory
723513		junseo	Split the sequence (APIO14_sequence)	C++17	11 / 100	2081 ms	7352 KiB

sequence

#include <bits/stdc++.h>
#pragma GCC optimize("O3")
#pragma GCC optimize("Ofast")
#define fi first
#define se second
#define eb emplace_back
#define ep emplace
#define all(v) (v).begin(), (v).end()
#define sz(v) (int)v.size()
#define rmin(r, x) r = min(r, x)
#define rmax(r, x) r = max(r, x)
#define ends ' '
#define endl '\n'
#define rep(i, s, e) for(int i = (s); i <= (e); ++i)
#define rep2(i, e, s) for(int i = (e); i >= (s); --i)
#define print(v) copy(all(v), ostream_iterator<int>(cout, " ")), cout << endl
#define fastio ios_base::sync_with_stdio(0), cin.tie(0)
using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef long double ld;
typedef vector<int> vi;

// #define LOCAL

const ll inf = 1e18;
const int maxn = 1e5 + 10;
const int maxk = 2e2 + 10;
const ll minx = 0, maxx = 1e9;

int N, K;
ll S[maxn];
pll D[maxk][maxn];

struct Line {
	ll a, b;
	int prv;
	Line(ll a=0, ll b=-inf, int prv=-1) : a(a), b(b), prv(prv) {}
	ll calc(ll x) { return a * x + b; }
};

struct Node {
	Line f;
	int l, r;
	Node() : l(0), r(r) {}
};

struct Lichao {
	Node tr[maxn];
	int C;
	Lichao() : C(1) {}
	void update(Line g, int nd=1, ll st=minx, ll ed=maxx) {
		while(true) {
			Line& f = tr[nd].f;
			ll mid = st+ed >> 1;
			if(f.calc(mid) < g.calc(mid))	swap(f, g);
			if(f.calc(st) < g.calc(st)) {
				ed = mid-1;
				nd = tr[nd].l = (tr[nd].l ?: ++C);
			}
			else if(f.calc(ed) < g.calc(ed)) {
				st = mid+1;
				nd = tr[nd].r = (tr[nd].r ?: ++C);
			}
			else	break;
		}
	}
	pll query(ll x, int nd=1, ll st=minx, ll ed=maxx) {
		pll ret = {-inf, -1};
		while(nd) {
			ll mid = st+ed >> 1;
			rmax(ret, pll(tr[nd].f.calc(x), tr[nd].f.prv));
			if(x <= mid) {
				ed = mid-1;
				nd = tr[nd].l;
			}
			else {
				st = mid+1;
				nd = tr[nd].r;
			}
		}
		return ret;
	}
};

int main() {
	#ifdef LOCAL
		freopen("input.txt", "r", stdin);
		freopen("output.txt", "w", stdout);
	#endif
	fastio;

	cin >> N >> K;
	rep(i, 1, N) {
		int x;	cin >> x;
		S[i] = S[i-1] + x;
	}
	rep(i, 1, N)	D[0][i] = pll(0, i);
	rep(k, 1, K) {
		Lichao T;
		rep(i, 1, N) {
			D[k][i] = T.query(S[i]);
			T.update(Line(S[i], D[k-1][i].fi - S[i]*S[i], i));
		}
	}
	vector<int> ans;
	int idx = N;
	rep2(k, K, 1) {
		idx = D[k][idx].se;
		ans.eb(idx);
	}
	reverse(all(ans));

	cout << D[K][N].fi << endl;
	for(auto& i : ans)	cout << i << ends;
	return 0;
}

Compilation message (stderr)

sequence.cpp: In constructor 'Node::Node()':
sequence.cpp:46:2: warning: 'Node::r' is initialized with itself [-Winit-self]
   46 |  Node() : l(0), r(r) {}
      |  ^~~~
sequence.cpp: In member function 'void Lichao::update(Line, int, ll, ll)':
sequence.cpp:56:15: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   56 |    ll mid = st+ed >> 1;
      |             ~~^~~
sequence.cpp: In member function 'pll Lichao::query(ll, int, ll, ll)':
sequence.cpp:72:15: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   72 |    ll mid = st+ed >> 1;
      |             ~~^~~

• Subtask 1: 11 / 11
• Subtask 2: 0 / 11
• Subtask 3: 0 / 11
• Subtask 4: 0 / 17
• Subtask 5: 0 / 21
• Subtask 6: 0 / 29