Submission #488159

#	Time	Username	Problem	Language	Result	Execution time	Memory
488159		ntabc05101	Split the sequence (APIO14_sequence)	C++14	100 / 100	857 ms	82028 KiB

sequence

#include<bits/stdc++.h>
using namespace std;

#define taskname ""

const long long inf = 1e17;

int main() {
	if (fopen(taskname".inp", "r")) {
		freopen(taskname".inp", "r", stdin);
		freopen(taskname".out", "w", stdout);
	}
	else {
		if (fopen(taskname".in", "r")) {
			freopen(taskname".in", "r", stdin);
			freopen(taskname".out", "w", stdout);
		}
	}

	cin.tie(0)->sync_with_stdio(0);

	int n, K; cin >> n >> K;
	long long a[n + 1];
	a[0] = 0;
	for (int i = 1; i <= n; i++) {
		cin >> a[i]; a[i] += a[i - 1];
	}

	vector<long long> dp[2];
	function<bool(int, int, int)> chk = [&](int i, int j, int t) {
		return (dp[0][i] - a[i] * a[i] - dp[0][j] + a[j] * a[j]) <= a[t] * (a[j] - a[i]);
	};
	function<bool(int, int, int)> chk2 = [&](int i, int j, int t) {
		return (dp[0][i] - a[i] * a[i] - dp[0][j] + a[j] * a[j]) * (a[t] - a[j]) >= (dp[0][j] - a[j] * a[j] - dp[0][t] + a[t] * a[t]) * (a[j] - a[i]);
	};

	//K++;
	dp[0].resize(n + 1); dp[1].resize(n + 1);
	int prf[n + 1][K + 1];
	memset(prf, 0, sizeof(prf));
	long long res = 0;
		dp[0][0] = 0;
		deque<int> deq;
		for (int k = 1; k <= K; k++) {
			deq.clear(); deq.push_back(0);
			for (int i = 1; i <= n; i++) {
				while (deq.size() > 1 && chk(deq[0], deq[1], i)) {
					deq.pop_front();
				}
				int j = deq.front();
				dp[1][i] = dp[0][j] + (a[i] - a[j]) * a[j];
				prf[i][k] = j;

				while (deq.size() > 1 && chk2(deq[deq.size() - 2], deq.back(), i)) {
					deq.pop_back();
				}
				deq.push_back(i);
			}
			dp[0] = dp[1];
		}

	cout << dp[0][n] << "\n";
	while (K > 0) {
		cout << prf[n][K] << " ";
		n = prf[n][K--];
	}
	cout << "\n";

	return 0;
}

/*
7 3
4 1 3 4 0 2 3
 */

Compilation message (stderr)

sequence.cpp: In function 'int main()':
sequence.cpp:41:12: warning: unused variable 'res' [-Wunused-variable]
   41 |  long long res = 0;
      |            ^~~
sequence.cpp:10:10: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   10 |   freopen(taskname".inp", "r", stdin);
      |   ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~
sequence.cpp:11:10: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   11 |   freopen(taskname".out", "w", stdout);
      |   ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
sequence.cpp:15:11: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   15 |    freopen(taskname".in", "r", stdin);
      |    ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~
sequence.cpp:16:11: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   16 |    freopen(taskname".out", "w", stdout);
      |    ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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