Submission #41955

#	Time	Username	Problem	Language	Result	Execution time	Memory
41955		fest	Split the sequence (APIO14_sequence)	C++14	71 / 100	322 ms	24752 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 = 10001, M = 201, 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];

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

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];
	for (int i = 0; i <= n; i++) for (int j = 0; j <= k; j++) dp[i][j] = -INF, pr[i][j] = -1;
	dp[0][0] = 0;
	vector<pair<int, pair<ll, int> > > lines;
	for (int bl = 1; bl <= k; bl++) {
		lines.clear();
		lines.pb({-pref[bl - 1], {dp[bl - 1][bl - 1], bl - 1}});
		for (int i = bl; i <= n; i++) {
			int x = pref[n] - pref[i];
			int l = 0;
			int r = SZ(lines) - 1;
			while (r - l > 1) {
				int mid = (l + r) / 2;
				if (x * 1ll * lines[mid].F + lines[mid].S.F < x * 1ll * lines[mid + 1].F + lines[mid + 1].S.F) l = mid;
				else r = mid;
			}
			if (x * 1ll * lines[l].F + lines[l].S.F < x * 1ll * lines[r].F + lines[r].S.F) swap(l, r);
			dp[i][bl] = x * 1ll * pref[i] + x * 1ll * lines[l].F + lines[l].S.F;
			pr[i][bl] = lines[l].S.S;
			while (SZ(lines) >= 2 && meet(lines.back().F, lines.back().S.F, -pref[i], dp[i][bl - 1]) > meet(lines[SZ(lines) - 2].F, lines[SZ(lines) - 2].S.F, -pref[i], dp[i][bl - 1]) - eps) lines.pop_back();
			while (!lines.empty() && lines.back().F == -pref[i] && lines.back().S.F == dp[i][bl - 1]) lines.pop_back();
			lines.pb({-pref[i], {dp[i][bl - 1], i}});
		}
	}
	int pos = 0;
	ll ans = -INF;
	for (int i = 1; i <= n; i++) {
		if (ans < dp[i][k]) {
			ans = dp[i][k];
			pos = i;
		}
	}
	vector<int> out;
	cout << ans << endl;
	int bl = k;
	while (pos > 0) {
		out.pb(pos);
		pos = pr[pos][bl];
		bl--;		
	}
	sort(All(out));
	for (auto i : out) printf("%d ", i);
	return 0;	
}

Compilation message (stderr)

sequence.cpp: In function 'int main()':
sequence.cpp:53:50: 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