Submission #506783

#	Time	Username	Problem	Language	Result	Execution time	Memory
506783		abc864197532	Money (IZhO17_money)	C++17	0 / 100	4 ms	8148 KiB

money

#include <bits/stdc++.h>
using namespace std;
#define lli long long int
#define mp make_pair
#define eb emplace_back
#define pb push_back
#define X first
#define Y second
#define pii pair<int, int>
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
void abc() {cout << endl;}
template <typename T, typename ...U> void abc(T i, U ...j) {
	cout << i << ' ', abc(j...);
}
template <typename T> void printv(T l, T r) {
	for (; l != r; ++l)
		cout << *l << " \n"[l + 1 == r];
}
#define test(x...) abc("[" + string(#x) + "]", x);
const int N = 1000001;

int dsu[N];

int Find(int x) {
	if (dsu[x] == x)
		return x;
	return dsu[x] = Find(dsu[x]);
}

void Union(int u, int v) {
	dsu[Find(u)] = Find(v);
}

int main () {
	ios::sync_with_stdio(false);
	cin.tie(0);
	int n;
	cin >> n;
	vector <int> a(n), cnt(N, 0);
	for (int i = 0; i < n; ++i) {
		cin >> a[i], --a[i], cnt[a[i]]++;
	}
	iota(dsu, dsu + N, 0);
	reverse(all(a));
	int ans = 0;
	for (int i = 0, j = 0; i < n; i = j) {
		ans++;
		if (i + 1 == n) {
			break;
		}
		while (j < n && a[i] == a[j])
			cnt[a[j]]--, j++;
		if (!cnt[a[i]])
			Union(a[i], a[i] - 1);
		int x = Find(a[i] - 1);
		while (j < n) {
			if (x != a[j])
				break;
			cnt[a[j]]--, j++;
			if (!cnt[x])
				Union(x, x - 1), x = Find(x);
		}
	}
	cout << ans << endl;
}
 
/*
6
3 6 4 5 1 2
*/

• Subtask 1: 0 / 9
• Subtask 2: 0 / 16
• Subtask 3: 0 / 20
• Subtask 4: 0 / 55