// #pragma GCC optimize ("Ofast")
// #pragma GCC target ("avx2")
#include <bits/stdc++.h>
using namespace std;
#ifdef LOCAL
#include <debug.h>
#else
#define debug(...)
#endif
#define ft front
#define bk back
#define st first
#define nd second
#define ins insert
#define ers erase
#define pb push_back
#define pf push_front
#define _pb pop_back
#define _pf pop_front
#define lb lower_bound
#define ub upper_bound
#define mtp make_tuple
#define bg begin
#define ed end
#define all(x) (x).bg(), (x).ed()
#define sz(x) (int)(x).size()
// #define int long long
typedef long long ll; typedef unsigned long long ull;
typedef double db; typedef long double ldb;
typedef pair<int, int> pi; typedef pair<ll, ll> pll;
typedef vector<int> vi; typedef vector<ll> vll; typedef vector<pi> vpi; typedef vector<pll> vpll;
typedef string str;
#define FOR(i, l, r) for (int i = (l); i <= (r); ++i)
#define FOS(i, r, l) for (int i = (r); i >= (l); --i)
#define FRN(i, n) for (int i = 0; i < (n); ++i)
#define FSN(i, n) for (int i = (n) - 1; i >= 0; --i)
#define EACH(i, x) for (auto &i : (x))
#define WHILE while
template<typename T> T gcd(T a, T b) { T d2 = (a | b) & -(a | b); a /= d2; b /= d2; WHILE(b) { a = a % b; swap(a, b); } return a * d2; }
template<typename T> T lcm(T a, T b) { return a / gcd(a, b) * b; }
void _assert(bool statement) { if (statement) return; cerr << "\n>> Assertion failed!\n"; exit(0); }
void _assert(bool statement, const str &message) { if (statement) return; cerr << "\n>> Assertion failed: " << message << '\n'; exit(0); }
void _error(const str &message) { cerr << "\n>> Error: " << message << '\n'; exit(0); }
#define file "TEST"
mt19937 rd(chrono::steady_clock::now().time_since_epoch().count());
ll rand(ll l, ll r) { return uniform_int_distribution<ll>(l, r)(rd); }
/*
----------------------------------------------------------------
END OF TEMPLATE
----------------------------------------------------------------
Tran The Bao - ghostwriter
Training for VOI23 gold medal
----------------------------------------------------------------
GOAT
----------------------------------------------------------------
*/
const int N = 5e5 + 5;
int n, q, a[N];
pi query[N];
void input(int test_id) {
cin >> n;
FOR(i, 1, n) cin >> a[i];
cin >> q;
FOR(i, 1, q) cin >> query[i].st >> query[i].nd;
}
namespace subtask12 {
const int N = 5005;
int d[N][N], maxx[N], pos[N], rs = 0;
int get(int l, int r) {
if (!pos[l]) {
maxx[l] = a[l];
pos[l] = l;
}
WHILE(pos[l] < r) {
++pos[l];
maxx[l] = max(maxx[l], a[pos[l]]);
}
return maxx[l];
}
void solve() {
FOR(len, 3, n)
FOR(l, 1, n - len + 1) {
int r = l + len - 1;
d[l][r] = max({d[l + 1][r], d[l][r - 1], a[l] + a[r] + get(l + 1, l + (r - l) / 2)});
}
FOR(i, 1, q) {
int l = query[i].st, r = query[i].nd;
cout << d[l][r] << '\n';
}
}
}
namespace subtask3 {
int maxx[N][18], LOG[N], rs = 0;
multiset<pi> s;
void build() {
FOR(i, 1, n) {
maxx[i][0] = a[i];
LOG[i] = log2(i);
}
FOR(j, 1, 17)
FOR(i, 1, n) {
if (i + (1 << j) - 1 > n) break;
maxx[i][j] = max(maxx[i][j - 1], maxx[i + (1 << (j - 1))][j - 1]);
}
}
int get(int l, int r) {
int l2 = LOG[r - l + 1];
return max(maxx[l][l2], maxx[r - (1 << l2) + 1][l2]);
}
int cal(int i) {
int rs = 0;
FOR(j, 1, i - 2) {
int mid = j + (i - j) / 2;
rs = max(rs, a[j] + a[i] + get(j + 1, mid));
}
FOR(j, i + 2, n) {
int mid = i + (j - i) / 2;
rs = max(rs, a[i] + a[j] + get(i + 1, mid));
}
FOR(j, 1, i - 1)
if (2 * i - j <= n)
rs = max(rs, a[j] + a[i] + get(2 * i - j, n));
return rs;
}
void solve() {
FOR(i, 1, n) {
s.ins({a[i], i});
if (sz(s) > 18) s.ers(s.bg());
}
build();
EACH(j, s) {
int i = j.nd;
rs = max(rs, cal(i));
}
cout << rs;
}
}
namespace subtask4 {
/*
This is a tough problem, although I have a beautiful observation for subtask3 but still fall to the trap.
Consider i and j, a[i] and a[j] must be bigger than every element that lies in [i + 1, j - 1] (as our claim) or else, we will
move i (or j) to the position that is bigger than a[i] (or a[j]) and the cost won't change.
What happen when we consider all pair i, j that sastified the condition? The answer is at most 2 * n. For all i, first we look at i - 1,
after that the first element bigger than a[i - 1] and continue... This is familar? A standard deque trick (monotonic stack trick).
The number of candidate pair (i, j) is at most 2 * n, now how to solve the problem with this observation is much more of a problem!
I've seen some submission that use some tricks to avoid lazy propagate but I think it's too complicated so I'll use lazy propagate segtree to
update and answer queries in a offline way.
Upd: Nah, that lazy avoiding trick isn't that hard, it's just because I'm so high right now :v.
*/
const int oo = 5e8 + 5;
struct Node {
int ab, c, ans;
Node() : ab(-oo), c(-oo), ans(-oo) {}
Node(int ab, int c, int ans) : ab(ab), c(c), ans(ans) {}
};
const int T = 2e6 + 5;
int qn[N], lp[N], ans[N];
vpi a1;
Node tr[T];
Node comb(const Node &a, const Node &b) { return Node(max(a.ab, b.ab), max(a.c, b.c), max({a.ans, b.ans, a.ab + b.c})); }
void upd(int i, int l, int r, int q, int v, bool type) {
if (r < q || l > q) return;
if (l == r) {
if (!type) tr[i].c = max(tr[i].c, v);
else tr[i] = Node(max(tr[i].ab, v), tr[i].c, max(tr[i].ans, v + tr[i].c));
return;
}
int mid = l + (r - l) / 2;
if (q <= mid) upd(i * 2, l, mid, q, v, type);
else upd(i * 2 + 1, mid + 1, r, q, v, type);
tr[i] = comb(tr[i * 2], tr[i * 2 + 1]);
}
Node get(int i, int l, int r, int ql, int qr) {
if (r < ql || l > qr) return Node();
if (ql <= l && r <= qr) return tr[i];
int mid = l + (r - l) / 2;
return comb(get(i * 2, l, mid, ql, qr), get(i * 2 + 1, mid + 1, r, ql, qr));
}
void solve() {
FOR(i, 1, n) {
int cur = i - 1;
WHILE(cur) {
a1.pb({cur, i});
if (a[cur] > a[i]) {
lp[i] = cur;
break;
}
cur = lp[cur];
}
}
sort(all(a1), [&](const pi &a, const pi &b) -> bool { return a.st > b.st; });
FOR(i, 1, q) qn[i] = i;
sort(qn + 1, qn + 1 + q, [&](const int &a, const int &b) { return query[a].st > query[b].st; });
int cp = 0;
FOR(i, 1, n) upd(1, 1, n, i, a[i], 0);
FOR(j, 1, q) {
int i = qn[j], l = query[i].st, r = query[i].nd;
WHILE(cp < sz(a1) && a1[cp].st >= l) {
upd(1, 1, n, 2 * a1[cp].nd - a1[cp].st, a[a1[cp].st] + a[a1[cp].nd], 1);
++cp;
}
ans[i] = get(1, 1, n, l, r).ans;
}
FOR(i, 1, q) cout << ans[i] << '\n';
}
}
void solve(int test_id) {
if (n <= 5000) {
subtask12::solve();
return;
}
if (n <= 2e5 && q == 1 && query[1].st == 1 && query[1].nd == n) {
subtask3::solve();
return;
}
subtask4::solve();
}
void reinit(int test_id) {
}
signed main() {
ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0);
// freopen(file".inp", "r", stdin);
// freopen(file".out", "w", stdout);
int test_num = 1;
// cin >> test_num; // comment if the problem does not requires multitest
FOR(i, 1, test_num) {
input(i); // input in noninteractive problems for case #i
solve(i); // main function to solve case #i
reinit(i); // reinit global data to default used in case #i
}
#ifdef LOCAL
cerr << "\nTime: " << setprecision(5) << fixed << (ldb)clock() / CLOCKS_PER_SEC << "ms.\n";
#endif
return 0;
}
/*
5
5 2 1 5 3
1
1 5
----------------------------------------------------------------
From Benq:
stuff you should look for
* int overflow, array bounds
* special cases (n=1?)
* do smth instead of nothing and stay organized
* WRITE STUFF DOWN
* DON'T GET STUCK ON ONE APPROACH
----------------------------------------------------------------
*/
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
10 ms |
23764 KB |
Output is correct |
2 |
Correct |
12 ms |
24212 KB |
Output is correct |
3 |
Correct |
13 ms |
24276 KB |
Output is correct |
4 |
Correct |
11 ms |
24276 KB |
Output is correct |
5 |
Correct |
11 ms |
24240 KB |
Output is correct |
6 |
Correct |
11 ms |
24216 KB |
Output is correct |
7 |
Correct |
11 ms |
24276 KB |
Output is correct |
8 |
Correct |
12 ms |
24212 KB |
Output is correct |
9 |
Correct |
12 ms |
24276 KB |
Output is correct |
10 |
Correct |
11 ms |
24276 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
10 ms |
23764 KB |
Output is correct |
2 |
Correct |
12 ms |
24212 KB |
Output is correct |
3 |
Correct |
13 ms |
24276 KB |
Output is correct |
4 |
Correct |
11 ms |
24276 KB |
Output is correct |
5 |
Correct |
11 ms |
24240 KB |
Output is correct |
6 |
Correct |
11 ms |
24216 KB |
Output is correct |
7 |
Correct |
11 ms |
24276 KB |
Output is correct |
8 |
Correct |
12 ms |
24212 KB |
Output is correct |
9 |
Correct |
12 ms |
24276 KB |
Output is correct |
10 |
Correct |
11 ms |
24276 KB |
Output is correct |
11 |
Correct |
342 ms |
104452 KB |
Output is correct |
12 |
Correct |
302 ms |
104404 KB |
Output is correct |
13 |
Correct |
285 ms |
104492 KB |
Output is correct |
14 |
Correct |
345 ms |
104404 KB |
Output is correct |
15 |
Correct |
325 ms |
104436 KB |
Output is correct |
16 |
Correct |
301 ms |
103756 KB |
Output is correct |
17 |
Correct |
287 ms |
103660 KB |
Output is correct |
18 |
Correct |
293 ms |
103756 KB |
Output is correct |
19 |
Correct |
302 ms |
104372 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
79 ms |
41228 KB |
Output is correct |
2 |
Correct |
88 ms |
41188 KB |
Output is correct |
3 |
Correct |
77 ms |
41216 KB |
Output is correct |
4 |
Correct |
80 ms |
41224 KB |
Output is correct |
5 |
Correct |
82 ms |
41212 KB |
Output is correct |
6 |
Correct |
80 ms |
40480 KB |
Output is correct |
7 |
Correct |
79 ms |
40464 KB |
Output is correct |
8 |
Correct |
81 ms |
40344 KB |
Output is correct |
9 |
Correct |
83 ms |
40740 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
10 ms |
23764 KB |
Output is correct |
2 |
Correct |
12 ms |
24212 KB |
Output is correct |
3 |
Correct |
13 ms |
24276 KB |
Output is correct |
4 |
Correct |
11 ms |
24276 KB |
Output is correct |
5 |
Correct |
11 ms |
24240 KB |
Output is correct |
6 |
Correct |
11 ms |
24216 KB |
Output is correct |
7 |
Correct |
11 ms |
24276 KB |
Output is correct |
8 |
Correct |
12 ms |
24212 KB |
Output is correct |
9 |
Correct |
12 ms |
24276 KB |
Output is correct |
10 |
Correct |
11 ms |
24276 KB |
Output is correct |
11 |
Correct |
342 ms |
104452 KB |
Output is correct |
12 |
Correct |
302 ms |
104404 KB |
Output is correct |
13 |
Correct |
285 ms |
104492 KB |
Output is correct |
14 |
Correct |
345 ms |
104404 KB |
Output is correct |
15 |
Correct |
325 ms |
104436 KB |
Output is correct |
16 |
Correct |
301 ms |
103756 KB |
Output is correct |
17 |
Correct |
287 ms |
103660 KB |
Output is correct |
18 |
Correct |
293 ms |
103756 KB |
Output is correct |
19 |
Correct |
302 ms |
104372 KB |
Output is correct |
20 |
Correct |
79 ms |
41228 KB |
Output is correct |
21 |
Correct |
88 ms |
41188 KB |
Output is correct |
22 |
Correct |
77 ms |
41216 KB |
Output is correct |
23 |
Correct |
80 ms |
41224 KB |
Output is correct |
24 |
Correct |
82 ms |
41212 KB |
Output is correct |
25 |
Correct |
80 ms |
40480 KB |
Output is correct |
26 |
Correct |
79 ms |
40464 KB |
Output is correct |
27 |
Correct |
81 ms |
40344 KB |
Output is correct |
28 |
Correct |
83 ms |
40740 KB |
Output is correct |
29 |
Correct |
1090 ms |
59520 KB |
Output is correct |
30 |
Correct |
915 ms |
53560 KB |
Output is correct |
31 |
Correct |
915 ms |
55728 KB |
Output is correct |
32 |
Correct |
1107 ms |
59600 KB |
Output is correct |
33 |
Correct |
1084 ms |
59592 KB |
Output is correct |
34 |
Correct |
1091 ms |
57244 KB |
Output is correct |
35 |
Correct |
1074 ms |
56872 KB |
Output is correct |
36 |
Correct |
1077 ms |
56828 KB |
Output is correct |
37 |
Correct |
1103 ms |
58324 KB |
Output is correct |
38 |
Correct |
934 ms |
59480 KB |
Output is correct |
39 |
Correct |
924 ms |
59620 KB |
Output is correct |
40 |
Correct |
914 ms |
56252 KB |
Output is correct |
41 |
Correct |
936 ms |
55600 KB |
Output is correct |
42 |
Correct |
909 ms |
55704 KB |
Output is correct |
43 |
Correct |
933 ms |
57352 KB |
Output is correct |
44 |
Correct |
952 ms |
59660 KB |
Output is correct |
45 |
Correct |
938 ms |
59564 KB |
Output is correct |
46 |
Correct |
943 ms |
56312 KB |
Output is correct |
47 |
Correct |
951 ms |
56052 KB |
Output is correct |
48 |
Correct |
932 ms |
55956 KB |
Output is correct |
49 |
Correct |
967 ms |
58100 KB |
Output is correct |
50 |
Correct |
1022 ms |
59560 KB |
Output is correct |
51 |
Correct |
1018 ms |
59532 KB |
Output is correct |
52 |
Correct |
978 ms |
57232 KB |
Output is correct |
53 |
Correct |
996 ms |
56744 KB |
Output is correct |
54 |
Correct |
991 ms |
56804 KB |
Output is correct |
55 |
Correct |
1008 ms |
58436 KB |
Output is correct |