Submission #306339

#	Time	Username	Problem	Language	Result	Execution time	Memory
306339		syy	Split the sequence (APIO14_sequence)	C++17	100 / 100	1895 ms	88532 KiB

sequence

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef long double ld;
#define FOR(i, a, b) for(int i = (int)a; i <= (int)b; i++)
#define DEC(i, a, b) for(int i = (int)a; i >= (int)b; i--)
typedef pair<ll, ll> pi;
typedef pair<pi, int> pii;
#define f first
#define s second
typedef vector<int> vi;
typedef vector<pi> vpi;
typedef vector<pii> vpii;
#define pb push_back
#define pf push_front
#define all(v) v.begin(), v.end()
#define INF (int) 1e9 + 100
#define LLINF (ll) 1e18
#define fastio ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0)

int n, k, ans[205][100005], arr[100005];
ll ss[100005];

inline ll cut(int x, int y, int m) {
	return (ss[y] - ss[m]) * (ss[m] - ss[x-1]);
}

deque <pii> dq;

pi func(pii line, ll x) {
    return pi(line.f.f * x + line.f.s, line.s);
}

pi query(int x, int idx) { // Finds the maximum of a mathematical function
    while (dq.size() > 1) {
		if (dq[1].s > idx) break;
		if (func(dq[0], x).f < func(dq[1], x).f) dq.pop_front(); 
		else break;
    }
    return func(dq[0], x);
}

double intersect(ll m1, ll c1, ll m2, ll c2) {
    return (double) (c1 - c2) / (double) (m2 - m1);
}

double intersect(pii p1, pii p2) {
    return intersect(p1.f.f, p1.f.s, p2.f.f, p2.f.s);
}

void insertline(ll m, ll c, int idx) { // y = mx + c
    pii line = pii(pi(m, c), idx);
    while (dq.size() > 1) { // To prevent seg fault
   	 ll si = dq.size();
   	 if (intersect(dq[si - 1], line) <= intersect(dq[si - 2], line)) { // Criteria for useless line: intersect 2 <= intersect 1
   		 dq.pop_back(); // Remove useless line
   	 } else break;
    }
    dq.push_back(line);
}


int main() {
	fastio; cin >> n >> k;
	FOR(i, 1, n) {
		cin >> arr[i];
		ss[i] = ss[i-1] + arr[i];
	}
	FOR(i, 0, k) {
		vpii toadd;
		FOR(j, i+1, n) {
			ll res;
			if (i == 0 or j == 1) res = 0;
			else {
				pi t = query(ss[j], j);
				res = t.f;
				ans[i][j] = t.s;
			}
			toadd.pb(pii(pi(ss[j], res - ss[j] * ss[j]), j));
			if (i == k and j == n) cout << res << "\n";
		}
		dq.clear();
		for(auto it:toadd) insertline(it.f.f, it.f.s, it.s);
	}
	DEC(i, k, 1) {
		cout << ans[i][n] << " ";
		n = ans[i][n];
	}
}

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