Submission #41978

#	Time	Username	Problem	Language	Result	Execution time	Memory
41978		fest	Split the sequence (APIO14_sequence)	C++14	71 / 100	2057 ms	51668 KiB

sequence

// fest
#include <bits/stdc++.h>	

#define pb push_back
#define F first
#define S second
#define y1 dasdasfasfas
#define x1 wqdadfasfasfas
#define All(c) c.begin(), c.end()
#define SZ(A) (int((A).size()))
#define umap unordered_map
#define FILENAME ""
#define __ fflush(stdout)

typedef long long ll;
typedef long double ld;    

using namespace std;

void FREOPEN() {
	#ifdef COMP
		freopen(".in", "r", stdin);
		freopen("1.out", "w", stdout);
	#endif
}                           

inline double Time() {return (clock() * 1.0) / CLOCKS_PER_SEC; }             

const int N = 100001, M = 40, inf = 1e9 * 2, MOD = (int)1e9 + 7;

char CH[N];

const double eps = 1e-14;

const ll INF = 1e18;

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

int pref[N], a[N], pr[N][M];

ll dp[N][M];

vector<pair<int, pair<ll, int> > > lines;

double meet(int a1, ll b1, int a2, ll b2) {
	return (double)(b2 - b1) / (double)(a1 - a2);
}

void calc(int real, int n, int k) {
	for (int i = 0; i <= n; i++) dp[i][0] = -INF, pr[i][0] = -1;
	dp[0][0] = 0;
	for (int bl = 1; bl <= k; bl++) {
		for (int i = 0; i <= n; i++) dp[i][bl % M] = -INF, pr[i][bl % M] = - 1;
		lines.clear();
		lines.pb({-pref[bl - 1], {dp[bl - 1][(bl - 1) % M], bl - 1}});
		int lef = 0;
		for (int i = bl; i <= n; i++) {
			int x = pref[real] - pref[i];
			while (lef + 1 < SZ(lines) && x * 1ll * lines[lef].F + lines[lef].S.F < x * 1ll * lines[lef + 1].F + lines[lef + 1].S.F) lef++;
			dp[i][bl % M] = x * 1ll * pref[i] + x * 1ll * lines[lef].F + lines[lef].S.F;
			pr[i][bl % M] = lines[lef].S.S;
			while (SZ(lines) >= 2 && meet(lines.back().F, lines.back().S.F, -pref[i], dp[i][(bl - 1) % M]) > meet(lines[SZ(lines) - 2].F, lines[SZ(lines) - 2].S.F, -pref[i], dp[i][(bl - 1) % M]) - eps) lines.pop_back();
			while (!lines.empty() && lines.back().F == -pref[i] && lines.back().S.F == dp[i][(bl - 1) % M]) lines.pop_back();
			lines.pb({-pref[i], {dp[i][(bl - 1) % M], i}});
			if (lef >= SZ(lines)) lef = SZ(lines) - 1;
		}
	}
}

int main() {
  
	FREOPEN();
	int n, k;
	cin >> n >> k;
	for (int i = 1; i <= n; i++) scanf("%d ", a + i);
	for (int i = 1; i <= n; i++) pref[i] = pref[i - 1] + a[i];
	calc(n, n, k);
  int pos = 0;
	ll ans = -INF;
	for (int i = 1; i <= n; i++) {
		if (ans < dp[i][k % M]) {
			ans = dp[i][k % M];
			pos = i;
		}
	}
	vector<int> out;
	cout << ans << endl;
	int bl = k;
	while (true) {
		int last = bl % M;
		bool ok = 0;
		for (int i = last; bl > 0; i = (i - 1 + M) % M, bl--) {
			if (ok && i == last) break;
			out.pb(pos);
			pos = pr[pos][i];
			ok = 1;
		}
		if (!bl) break;
		calc(n, pos, bl);	
	}
	sort(All(out));
	for (auto i : out) printf("%d ", i);
	return 0;	
}

Compilation message (stderr)

sequence.cpp: In function 'int main()':
sequence.cpp:76:50: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  for (int i = 1; i <= n; i++) scanf("%d ", a + i);
                                                  ^

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