Submission #377913

#	Time	Username	Problem	Language	Result	Execution time	Memory
377913		ritul_kr_singh	Split the sequence (APIO14_sequence)	C++17	100 / 100	1872 ms	94724 KiB

sequence

#include <bits/stdc++.h>
using namespace std;
#define int long long
#define sp << ' ' <<
#define nl << '\n'
 
deque<array<int, 3>> hull[200+1];
 
int f(int x, int i, int j){
	if(j<0) j += hull[i].size();
	return hull[i][j][0]*x + hull[i][j][1] - x*x;
}
 
bool bad(int m, int c, int i){
	int x1 = c-hull[i][0][1];
	int d1 = hull[i][0][0]-m;
	if(d1<0) d1 *= -1LL, x1 *= -1LL;
 
	c = hull[i][1][1], m = hull[i][1][0];
 
	int x2 = c-hull[i][0][1];
	int d2 = hull[i][0][0]-m;
	if(d2<0) d2 *= -1LL, x2 *= -1LL;
 
	return x1*d2 >= x2*d1;
}
 
signed main(){
    ios_base::sync_with_stdio(false); cin.tie(nullptr);
    int n, k; cin >> n >> k;
    int a[n], ans = 0, ind = 0;
    for(int &i : a) cin >> i;
    for(int i=n-2; i>=0; --i) a[i] += a[i+1];
 
	hull[0].push_back({a[0], 0});
	int32_t p[n][k];
 
	for(int i=1; i<n; ++i){
		for(int j=k-1; j>=0; --j){
			if(hull[j].empty()) continue;
			while(hull[j].size()>1 and f(a[i], j, -2) >= f(a[i], j, -1)) hull[j].pop_back();
			int dp = f(a[i], j, -1);
			p[i][j] = hull[j].back()[2];
 
			int m = a[i];
 
			while(!hull[j+1].empty()){
				if(hull[j+1][0][0]==m){
					dp = max(dp, hull[j+1][0][1]);
					hull[j+1].pop_front();
				}else if(hull[j+1].size() > 1 and bad(m, dp, j+1)){
					hull[j+1].pop_front();
				}else break;
			}
			hull[j+1].push_front({m, dp, i});
			if(dp >= ans){
				ans = dp;
				ind = i;
			}
		}
	}
	// for(auto i : hull[1]) cout << i[2] nl;
	vector<int> res = {ind};
	for(int j=k-1; j>=0; --j){
		res.push_back(p[ind][j]);
		ind = res.back();
	}
	cout << ans nl;
	for(int i=res.size()-2; i>=0; --i) cout << res[i] << ' ';
}

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