Submission #888270

#	Time	Username	Problem	Language	Result	Execution time	Memory
888270		drAKu	Money (IZhO17_money)	C++17	0 / 100	2 ms	4444 KiB

money

#include <bits/stdc++.h>

using namespace std;

using ll = long long;

mt19937 rng(228);
const int N = 1e6 + 1;
int a[N], ans[N];
const int G = (1 << 20);
int t[2 * G];
int get(int ql, int qr) {
    int ans = 0;
    for (ql += G, qr += G; ql <= qr; ql >>= 1, qr >>= 1) {
        if (ql & 1) ans ^= t[ql++];
        if (~qr & 1) ans ^= t[qr--];
    }
    return ans;
}
void upd(int ql, int val) {
    for (ql += G, t[ql] ^= val, ql >>= 1; ql; ql >>= 1) t[ql] = t[ql << 1] ^ t[ql << 1 | 1];
}

signed main() {
    cin.tie(nullptr)->sync_with_stdio(false);
    
    int n;
    cin >> n;
    for (int i = 0; i < n; i++) cin >> a[i];
    for (int i = 1; i < n; i++) {
        if (a[i-1] > a[i]) continue;
        if (a[i-1] == a[i] || a[i] == a[i-1] + 1) {
            ans[i] = 1;
            if (ans[i-1] == 1 && a[i-1] + 1 <= a[i] - 1) {
                int t = rng();
                upd(a[i-2] + 1, t);
                upd(a[i] - 1, t);
            }
            continue;
        }
        int good = get(a[i-1], a[i]);
        if (good == 0) {
            ans[i] = 1;
            int t = rng();
            upd(a[i-1] + 1, t);
            upd(a[i] - 1, t);
            if (ans[i-1] == 1) {
                t = rng();
                upd(a[i-2] + 1, t);
                upd(a[i] - 1, t);
            }
        }
    }
    cout << n - accumulate(ans, ans + N, 0) << "\n";
}

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