Submission #536095

#	Time	Username	Problem	Language	Result	Execution time	Memory
536095		mansur	Split the sequence (APIO14_sequence)	C++17	49 / 100	70 ms	131072 KiB

sequence

#include<bits/stdc++.h>	
 
#pragma GCC optimize("Ofast,no-stack-protector,unroll-loops,fast-math,O3")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")

using namespace std;
 
#define all(a) a.begin(), a.end()                                                   
#define rall(a) a.rbegin(), a.rend()
#define ll long long
#define pb push_back
#define sz(a) a.size()
#define nl '\n'
#define popb pop_back()                                                                   
#define ld double
#define ull unsigned long long
#define ff first                                         
#define ss second  
#define fix fixed << setprecision                                                                                                  	
#define pii pair<int, int>                          
#define E exit (0)
#define int long long
 
const int inf = 1e15, N = 1e5 + 5, mod = 1e9 + 7;                    
 
double eps = 1e-6;

bool fl = 0;
 
vector<pii> dir = {{1, 0}, {0, 1}, {-1, 0}, {0, -1}};

int ntr(pii a, pii b) {
	int x = b.ff - a.ff;
	int y = a.ss - b.ss;
	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 i = 0; i <= k; i++) dp[0][i] = 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].ff.ff <= p[i]) l++;
			dp[i][j] = (dp[i - 1][j], s[l - 1].ss.ff + s[l - 1].ss.ss * p[i]);
			if (dp[i][j] == dp[i - 1][j]) {
				pr[i][j] = {i - 1, j};
			}else {
				pr[i][j] = {s[l - 1].ff.ss, j - 1};
			}
		}
		s.clear();
		for (int i = 1; i <= n; i++) {
			int a = dp[i][j] - p[i] * p[i], b = p[i];
			if (sz(s) && a == s.back().ss.ff && b == s.back().ss.ss) continue;
			int ps = -inf;
			while (sz(s) && ntr({a, b}, s.back().ss) <= s.back().ff.ff) s.popb;
			if (sz(s)) ps = ntr({a, b}, s.back().ss);
			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].ff, j1 = pr[i][j].ss;
	 	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:58:13: 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]
   58 |    while (l < sz(s) && s[l].ff.ff <= p[i]) l++;
      |             ^
sequence.cpp:59:27: warning: left operand of comma operator has no effect [-Wunused-value]
   59 |    dp[i][j] = (dp[i - 1][j], s[l - 1].ss.ff + s[l - 1].ss.ss * p[i]);
      |                ~~~~~~~~~~~^
sequence.cpp: At global scope:
sequence.cpp:91:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   91 | 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