Submission #644800

#	Time	Username	Problem	Language	Result	Execution time	Memory
644800		ghostwriter	Money (IZhO17_money)	C++14	100 / 100	1379 ms	88516 KiB

money

#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], d[N], root = 0, cnt = 0;
set<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;
    		}
    		bool ok1 = 0, ok2 = 0;
    		if (!s.empty() && *--s.ed() >= a[r[i]]) {
    			int v = *s.lb(a[r[i]]);
    			if (v == a[r[i]]) ok1 = 1;
    		}
    		if (!s.empty() && *--s.ed() > a[r[i]]) {
    			int v = *s.ub(a[r[i]]);
    			if (v < a[r[i] + 1]) ok2 = 1;
    		}
    		if (ok2) break;
    		if (!ok1) {
    			++r[i];
    			continue;
    		}
			if (a[r[i]] == a[i]) {
				++r[i];
				continue;
			}
			break;
    	}
    	s.insert(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 (stderr)

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:116:5: note: in expansion of macro 'FOS'
  116 |     FOS(i, n - 1, 1) {
      |     ^~~

• Subtask 1: 9 / 9
• Subtask 2: 16 / 16
• Subtask 3: 20 / 20
• Subtask 4: 55 / 55