Yellow Yacht

// TOO SLOW, QAQ ;___;





#include <bits/stdc++.h>
using namespace std;
#define FOR(i, a, b) for (int i=a; i<(b); i++)
#define IO ios_base::sync_with_stdio(0); cin.tie(0)
#define ff first
#define ss second
#define pb push_back
#define INF 2147483647
#define LINF (1LL<<62LL)
typedef long long ll;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;

int m;

#define N (1<<15)
ll t[2*N];

void add(int k, ll x) {
	k += N;
	t[k] += x;
	for (k /= 2; k >= 1; k /= 2) {
		t[k] = max(t[2*k], t[2*k+1]);
	}
}

ll maxq(int a, int b) {
	a += N; b += N;
	ll r = 0;
	while (a <= b) {
		if (a % 2 == 1) r = max(r, t[a++]);
		if (b % 2 == 0) r = max(r, t[b--]);
		a /= 2; b /= 2;
	}
	return r;
}

ll V[10004];

int main() {
	IO; cin>>m;
	FOR(i,0,m+1) {
		ll x; cin>>x; V[i] = x;
		add(i,x);
	}
	ll r = -LINF;
	FOR(i,0,m+1) {
		FOR(j,i,m+1) {
			// calculate where k can be...
			if (i+2*j > m) break;
			int maxk = m - (j+i);
			r = max(r, V[i]+V[j]+maxq(j,maxk));
			/*
			ll left = V[i]+V[j];
			ll mx = maxq(j, maxk);
			if (r < left + mx) {
				
			}*/
		}
	}
	cout << r;
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: ACCEPTED

Test 6

Verdict: ACCEPTED

Test 7

Verdict: ACCEPTED

Test 8

Verdict: ACCEPTED

Test 9

Verdict: ACCEPTED

Test 10

Verdict: ACCEPTED

Test 11

Verdict: ACCEPTED

Test 12

Verdict: ACCEPTED

Test 13

Verdict: ACCEPTED

Test 14

Verdict: ACCEPTED

Test 15

Verdict: ACCEPTED

Test 16

Verdict: ACCEPTED

Test 17

Verdict: ACCEPTED

Test 18

Verdict: ACCEPTED

Test 19

Verdict: ACCEPTED

Test 20

Verdict: ACCEPTED

Test 21

Verdict: ACCEPTED

Test 22

Verdict: ACCEPTED

Test 23

Verdict: ACCEPTED

Test 24

Verdict: ACCEPTED

Test 25

Verdict: ACCEPTED

Test 26

Verdict: ACCEPTED

Test 27

Verdict: ACCEPTED

Test 28

Verdict: ACCEPTED

Test 29

Verdict: ACCEPTED

Test 30

Verdict: ACCEPTED

Test 31

Verdict: ACCEPTED

Test 32

Verdict: ACCEPTED

Test 33

Verdict: ACCEPTED

Test 34

Verdict: ACCEPTED

Test 35

Verdict: ACCEPTED

Test 36

Verdict: ACCEPTED

Test 37

Verdict: ACCEPTED

Test 38

Verdict: ACCEPTED

Test 39

Verdict: ACCEPTED

Test 40

Verdict: ACCEPTED