#include <bits/stdc++.h>
using namespace std;
#ifdef LOCAL
#include <debug.h>
#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()
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;
template<typename T> T gcd(T a, T b) { return (b == 0? a : gcd(b, a % b)); }
template<typename T> T lcm(T a, T b) { return a / gcd(a, b) * b; }
#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
#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
----------------------------------------------------------------
DIT ME CHUYEN BAO LOC
----------------------------------------------------------------
*/
const int oo = 1e9 + 5;
struct Node {
int opt, left, right;
Node() : opt(oo), left(0), right(0) {}
Node(int opt, int left, int right) : opt(opt), left(left), right(right) {}
};
const int N = 1e6 + 5;
const int Nx2 = 2e6 + 5;
int n, a[N], r[N], c[N], d[N], root = 0, cnt = 0;
multiset<int> s;
Node tr[Nx2];
void upd(int &i, int l, int r, int q, int v) {
if (!i) i = ++cnt;
if (r < q || l > q) return;
if (l == r) {
tr[i].opt = min(tr[i].opt, v);
return;
}
int mid = l + (r - l) / 2;
upd(tr[i].left, l, mid, q, v);
upd(tr[i].right, mid + 1, r, q, v);
tr[i].opt = min(tr[tr[i].left].opt, tr[tr[i].right].opt);
}
int get(int &i, int l, int r, int ql, int qr) {
if (!i) i = ++cnt;
if (r < ql || l > qr) return oo;
if (ql <= l && r <= qr) return tr[i].opt;
int mid = l + (r - l) / 2;
return min(get(tr[i].left, l, mid, ql, qr), get(tr[i].right, mid + 1, r, ql, qr));
}
signed main() {
ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0);
// freopen(file".inp", "r", stdin);
// freopen(file".out", "w", stdout);
cin >> n;
FOR(i, 1, n) cin >> a[i];
FOR(i, 1, n) {
r[i] = max(r[i - 1], i);
WHILE(r[i] < n && a[r[i]] <= a[r[i] + 1]) {
if (a[r[i]] == a[r[i] + 1]) {
++r[i];
continue;
}
if (s.empty() || *--s.ed() <= a[r[i]]) {
if (a[r[i]] == a[i]) {
++r[i];
continue;
}
if (c[a[r[i]]]) break;
++r[i];
continue;
}
int v = *s.ub(a[r[i]]);
if (v < a[r[i] + 1]) break;
if (c[a[r[i]]]) break;
++r[i];
}
s.insert(a[i]);
++c[a[i]];
}
d[n] = 1;
upd(root, 1, n, n, d[n]);
FOS(i, n - 1, 1) {
if (r[i] == n) d[i] = 1;
else d[i] = get(root, 1, n, i + 1, r[i] + 1) + 1;
upd(root, 1, n, i, d[i]);
}
cout << d[1];
return 0;
}
/*
6
3 6 4 5 1 2
----------------------------------------------------------------
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
----------------------------------------------------------------
*/
Compilation message
money.cpp: In function 'int main()':
money.cpp:30:31: warning: unnecessary parentheses in declaration of 'i' [-Wparentheses]
30 | #define FOR(i, l, r) for (int (i) = (l); (i) <= (r); ++(i))
| ^
money.cpp:84:5: note: in expansion of macro 'FOR'
84 | FOR(i, 1, n) cin >> a[i];
| ^~~
money.cpp:30:31: warning: unnecessary parentheses in declaration of 'i' [-Wparentheses]
30 | #define FOR(i, l, r) for (int (i) = (l); (i) <= (r); ++(i))
| ^
money.cpp:85:5: note: in expansion of macro 'FOR'
85 | FOR(i, 1, n) {
| ^~~
money.cpp:31:31: warning: unnecessary parentheses in declaration of 'i' [-Wparentheses]
31 | #define FOS(i, r, l) for (int (i) = (r); (i) >= (l); --(i))
| ^
money.cpp:111:5: note: in expansion of macro 'FOS'
111 | FOS(i, n - 1, 1) {
| ^~~
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
13 ms |
23764 KB |
Output is correct |
| 2 |
Correct |
12 ms |
23732 KB |
Output is correct |
| 3 |
Correct |
10 ms |
23820 KB |
Output is correct |
| 4 |
Incorrect |
12 ms |
23764 KB |
Output isn't correct |
| 5 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
13 ms |
23764 KB |
Output is correct |
| 2 |
Correct |
12 ms |
23732 KB |
Output is correct |
| 3 |
Correct |
10 ms |
23820 KB |
Output is correct |
| 4 |
Incorrect |
12 ms |
23764 KB |
Output isn't correct |
| 5 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
13 ms |
23764 KB |
Output is correct |
| 2 |
Correct |
12 ms |
23732 KB |
Output is correct |
| 3 |
Correct |
10 ms |
23820 KB |
Output is correct |
| 4 |
Incorrect |
12 ms |
23764 KB |
Output isn't correct |
| 5 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
13 ms |
23764 KB |
Output is correct |
| 2 |
Correct |
12 ms |
23732 KB |
Output is correct |
| 3 |
Correct |
10 ms |
23820 KB |
Output is correct |
| 4 |
Incorrect |
12 ms |
23764 KB |
Output isn't correct |
| 5 |
Halted |
0 ms |
0 KB |
- |
