Submission #792371

#	Time	Username	Problem	Language	Result	Execution time	Memory
792371		Nhoksocqt1	Doktor (COCI17_doktor)	C++17	100 / 100	110 ms	34124 KiB

doktor

#include<bits/stdc++.h>
using namespace std;

#define inf 0x3f3f3f3f
#define sz(x) int((x).size())
#define fi first
#define se second
typedef long long ll;
typedef pair<int, int> ii;

template<class X, class Y>
	inline bool maximize(X &x, const Y &y) {return (x < y ? x = y, 1 : 0);}
template<class X, class Y>
	inline bool minimize(X &x, const Y &y) {return (x > y ? x = y, 1 : 0);}

mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
int Random(int l, int r) {
    return uniform_int_distribution<int>(l, r)(rng);
}

const int MAXN = 500005;

vector<int> B[MAXN];
int a[MAXN], sum[MAXN], cnt[4 * MAXN], nArr;

void brute(void) {
    int res(0), l(0), r(0);
    for (int i = 1; i <= nArr; ++i) {
        for (int j = i; j <= nArr; ++j) {
            reverse(a + i, a + j + 1);

            int cnt(0);
            for (int k = 1; k <= nArr; ++k)
                cnt += (a[k] == k);

            reverse(a + i, a + j + 1);
            if(cnt > res) {
                res = cnt;
                l = i, r = j;
            }
        }
    }

    cout << res << '\n' << a[l] << ' ' << a[r] << '\n';
}

void process() {
    cin >> nArr;

    int cnto(0);
    for (int i = 1; i <= nArr; ++i) {
        cin >> a[i];
        //if(i == 1) { for (int i = 1; i <= nArr; ++i) a[i] = i; shuffle(a + 1, a + nArr + 1, rng); for (int i = 1; i <= nArr; ++i) cout << a[i] << " \n"[i == nArr]; }

        B[max(i, a[i])].push_back(min(i, a[i]));
        cnto += (a[i] == i);
    }


    int maxcnt(cnto), l(1), r(1);
    for (int i = 1; i <= nArr; ++i) {
        sum[i] = sum[i - 1];
        for (int it = 0; it < sz(B[i]); ++it) {
            int j(B[i][it]);
            if(i != j) {
                ++cnt[i + j];
                int midc = ((i - j + 1) & 1) ? (a[j + (i - j + 1) / 2] == (j + (i - j + 1) / 2)) : 0;
                //cout << j << ' ' << i << ' ' << i + j << ' ' << cnt[i + j] << ' ' << sum[i] - sum[j - 1] - midc << '\n';
                if(maxcnt < cnt[i + j] + cnto - sum[i] + sum[j - 1] + midc) {
                    maxcnt = cnt[i + j] + cnto - sum[i] + sum[j - 1] + midc;
                    l = j, r = i;
                }
            } else {
                ++sum[i];
            }
        }
    }

    //brute();
    //cout << maxcnt << '\n';
    cout << a[l] << ' ' << a[r] << '\n';
}

int main() {
    ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);

    process();
    return 0;
}

• Subtask 1: 10 / 10
• Subtask 2: 10 / 10
• Subtask 3: 10 / 10
• Subtask 4: 10 / 10
• Subtask 5: 10 / 10
• Subtask 6: 10 / 10
• Subtask 7: 10 / 10
• Subtask 8: 10 / 10
• Subtask 9: 10 / 10
• Subtask 10: 10 / 10