Submission #540975

#	Time	Username	Problem	Language	Result	Execution time	Memory
540975		mansur	Split the sequence (APIO14_sequence)	C++17	49 / 100	95 ms	131072 KiB

sequence

#include<bits/stdc++.h>	
 
using namespace std;
 
#define all(a) a.begin(), a.end()                                                   
#define rall(a) a.rbegin(), a.rend()
#define sz(a) a.size()
#define int long long               
#define pb push_back
#define vt vector
#define s second
#define f first
#define nl '\n'

using pii = pair<int, int>;
using ll = long long;

vt<pii> dir = {{1, 0}, {0, 1}, {-1, 0}, {0, -1}};
 
const int inf = 1e15, N = 1e6 + 5, mod = 1e9 + 7;                    
 
double eps = 1e-6;

bool fl = 0;

int ntr(pii a, pii b) {
	int x = b.f - a.f;
	int y = a.s - b.s;
	return (x + y - 1) / y;
}
 
void solve() {
	int n, k;
	cin >> n >> k;          	
	int p[n + 1];
	pii pr[n + 1][k + 1];
	p[0] = 0;
	for (int i = 1, a; i <= n; i++) {
		cin >> a;
		p[i] = p[i - 1] + a;
	}
	int dp[n + 1][k + 1];
	for (int i = 1; i <= n; i++) {
		for (int s = 1; s <= k; s++) dp[i][s] = -inf;
	}         
	for (int s = 0; s <= k; s++) dp[0][s] = 0;
	vector<pair<pii, pii>> s;
	s.pb({{-inf, -1}, {0, 0}});
	for (int j = 0; j <= k; j++) {
		int l = 0;
		for (int i = 1; i <= n; i++) {
			while (l < sz(s) && s[l].f.f <= p[i]) l++;
			dp[i][j] = max(dp[i - 1][j], s[l - 1].s.f + s[l - 1].s.s * p[i]);
			if (dp[i][j] == dp[i - 1][j]) {
				pr[i][j] = {i - 1, j};
			}else {
				pr[i][j] = {s[l - 1].f.s, j - 1};
			}
		}
		s.clear();
		for (int i = 1; i <= n; i++) {
			int a = dp[i][j] - p[i] * p[i], b = p[i];
			int ps = -inf;
			if (sz(s) && b == s.back().s.s) {
				if (a > s.back().s.f) {
				 	s.pop_back();
				 	while (sz(s) && ntr({a, b}, s.back().s) <= s.back().f.f) s.pop_back();
				 	if (sz(s)) ps = ntr({a, b}, s.back().s);
					s.pb({{ps, i}, {a, b}});
				}
				continue;
			}
			while (sz(s) && ntr({a, b}, s.back().s) <= s.back().f.f) s.pop_back();
			if (sz(s)) ps = ntr({a, b}, s.back().s);
			s.pb({{ps, i}, {a, b}});  
		}
	}
	cout << dp[n][k] << nl;
	vector<int> ans;
	int i = n, j = k;
	while (j > 0) {
	 	int i1 = pr[i][j].f, j1 = pr[i][j].s;
	 	if (j1 == j) {
	 		i = i1, j = j1;
	 		continue;
	 	}
	 	ans.pb(i1);
	 	i = i1, j = j1;
	}
	for (auto x: ans) cout << x << ' ';
}   
 
main() {                                                         
	//freopen("input.txt", "r", stdin);                                                                                     
	//freopen("output.txt", "w", stdout);                                                                                     
	ios_base::sync_with_stdio(NULL);                                                                                       
	cin.tie(NULL);
	int tp = 1;
	if (fl) cin >> tp;
	while (tp--) solve();
}

Compilation message (stderr)

sequence.cpp: In function 'void solve()':
sequence.cpp:52:13: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<std::pair<std::pair<long long int, long long int>, std::pair<long long int, long long int> > >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   52 |    while (l < sz(s) && s[l].f.f <= p[i]) l++;
      |             ^
sequence.cpp: At global scope:
sequence.cpp:93:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   93 | main() {
      | ^~~~

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