Submission #1694529


Source Code Expand

#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <algorithm>
#include <vector>
#include <queue>
#include <stack>
#include <cmath>

using namespace std;

const int MAXN = 100000 + 1000;
const int MOD = 1000000000 + 7;
const int INF = 0x1f1f1f1f;

int n, p[MAXN];
int ans = 1;
vector<int> redg[MAXN];
vector<int> vc, vl;
bool vis[MAXN], onc[MAXN];
int cnt[MAXN], f[MAXN];

int get_len(int x)
{
	vis[x] = true;
	int ret = 0;
	for(int i = 0; i < redg[x].size(); i++)
		if(!onc[redg[x][i]])
			ret = ret == 0 ? get_len(redg[x][i]) + 1 : -INF;
	return ret;
}

int find_circle(int x)
{
	vis[x] = true;
	int y = p[x], t = vis[y] ? y : find_circle(y);
	if(t)
		onc[x] = true, vc.push_back(x);
	return t == x ? 0 : t;
}

void work()
{
	for(int i = 1; i <= n; i++)
		redg[p[i]].push_back(i);
	for(int i = 1; i <= n; i++)
		if(!vis[i])
		{
			vc.clear(), vl.clear();
			find_circle(i);	
			reverse(vc.begin(), vc.end());
			int last = -1;
			for(int j = 0; j < vc.size(); j++)
			{
				int x = vc[j], t = get_len(x);
				if(t < 0)
				{
					ans = 0; return ;
				}
				else if(t > 0)
					last = j;
				vl.push_back(t);
				// cerr << vc[j] << ' ' << vl[j] << endl;
			}
			// cerr << endl;
			if(last < 0)
			{
				cnt[vc.size()]++;
				continue;
			}
			else
			{
				for(int j = 0; j < vc.size(); j++)
					if(vl[j] > 0)
					{
						int l1 = vl[j], l2 = (j - last + vc.size() - 1) % vc.size() + 1;
						// cerr << l1 << ' ' << l2 << endl;
						if(l1 < l2)
							ans = (ans * 2) % MOD;
						else if(l1 == l2)
							ans = (ans * 1) % MOD;
						else
							ans = 0;
						last = j;
					}
			}
		}
	for(int i = 1; i <= n; i++)
		if(cnt[i])
		{
			int lam = (i == 1 || i % 2 == 0 ? 1 : 2);
			f[0] = 1;
			for(int j = 1; j <= cnt[i]; j++)
			{
				f[j] = (long long)f[j - 1] * lam % MOD;
				if(j - 2 >= 0)
					f[j] = (f[j] + (long long)f[j - 2] * (j - 1) % MOD * i) % MOD;
			}
			ans = (long long)ans * f[cnt[i]] % MOD;
		}
}

int main()
{
	ios::sync_with_stdio(false);
	// freopen("1.in", "r", stdin);
	// freopen("1.out", "w", stdout);

	cin >> n;
	for(int i = 1; i <= n; i++)
		cin >> p[i];

	work();
	cout << ans << endl;


	return 0;
}

Submission Info

Submission Time
Task E - Next or Nextnext
User ct123098
Language C++14 (GCC 5.4.1)
Score 1400
Code Size 2294 Byte
Status AC
Exec Time 26 ms
Memory 10620 KB

Judge Result

Set Name Sample All
Score / Max Score 0 / 0 1400 / 1400
Status
AC × 5
AC × 59
Set Name Test Cases
Sample 0_00.txt, 0_01.txt, 0_02.txt, 0_03.txt, 0_04.txt
All 0_00.txt, 0_01.txt, 0_02.txt, 0_03.txt, 0_04.txt, 1_00.txt, 1_01.txt, 1_02.txt, 1_03.txt, 1_04.txt, 1_05.txt, 1_06.txt, 1_07.txt, 1_08.txt, 1_09.txt, 1_10.txt, 1_11.txt, 1_12.txt, 1_13.txt, 1_14.txt, 1_15.txt, 1_16.txt, 1_17.txt, 1_18.txt, 1_19.txt, 1_20.txt, 1_21.txt, 1_22.txt, 1_23.txt, 1_24.txt, 1_25.txt, 1_26.txt, 1_27.txt, 1_28.txt, 1_29.txt, 1_30.txt, 1_31.txt, 1_32.txt, 1_33.txt, 1_34.txt, 1_35.txt, 1_36.txt, 1_37.txt, 1_38.txt, 1_39.txt, 1_40.txt, 1_41.txt, 1_42.txt, 1_43.txt, 1_44.txt, 1_45.txt, 1_46.txt, 1_47.txt, 1_48.txt, 1_49.txt, 1_50.txt, 1_51.txt, 1_52.txt, 1_53.txt
Case Name Status Exec Time Memory
0_00.txt AC 3 ms 2688 KB
0_01.txt AC 3 ms 2688 KB
0_02.txt AC 3 ms 2688 KB
0_03.txt AC 3 ms 2688 KB
0_04.txt AC 3 ms 2688 KB
1_00.txt AC 3 ms 2688 KB
1_01.txt AC 19 ms 6784 KB
1_02.txt AC 21 ms 6528 KB
1_03.txt AC 21 ms 6528 KB
1_04.txt AC 23 ms 7932 KB
1_05.txt AC 24 ms 8444 KB
1_06.txt AC 26 ms 10616 KB
1_07.txt AC 23 ms 6400 KB
1_08.txt AC 25 ms 10616 KB
1_09.txt AC 22 ms 10108 KB
1_10.txt AC 25 ms 10616 KB
1_11.txt AC 24 ms 10360 KB
1_12.txt AC 25 ms 9340 KB
1_13.txt AC 25 ms 9596 KB
1_14.txt AC 24 ms 8444 KB
1_15.txt AC 25 ms 9464 KB
1_16.txt AC 25 ms 9464 KB
1_17.txt AC 25 ms 9464 KB
1_18.txt AC 25 ms 10492 KB
1_19.txt AC 26 ms 10620 KB
1_20.txt AC 25 ms 10492 KB
1_21.txt AC 26 ms 10616 KB
1_22.txt AC 25 ms 8696 KB
1_23.txt AC 25 ms 8696 KB
1_24.txt AC 25 ms 8692 KB
1_25.txt AC 25 ms 8696 KB
1_26.txt AC 23 ms 8316 KB
1_27.txt AC 24 ms 8448 KB
1_28.txt AC 23 ms 8320 KB
1_29.txt AC 23 ms 8448 KB
1_30.txt AC 23 ms 8064 KB
1_31.txt AC 22 ms 7040 KB
1_32.txt AC 23 ms 7932 KB
1_33.txt AC 23 ms 7932 KB
1_34.txt AC 23 ms 6400 KB
1_35.txt AC 23 ms 6656 KB
1_36.txt AC 23 ms 6272 KB
1_37.txt AC 23 ms 6528 KB
1_38.txt AC 23 ms 7168 KB
1_39.txt AC 24 ms 6784 KB
1_40.txt AC 23 ms 6912 KB
1_41.txt AC 21 ms 7040 KB
1_42.txt AC 22 ms 6272 KB
1_43.txt AC 23 ms 6400 KB
1_44.txt AC 23 ms 6400 KB
1_45.txt AC 23 ms 6400 KB
1_46.txt AC 23 ms 5632 KB
1_47.txt AC 23 ms 5504 KB
1_48.txt AC 24 ms 5632 KB
1_49.txt AC 23 ms 5632 KB
1_50.txt AC 22 ms 6272 KB
1_51.txt AC 22 ms 6272 KB
1_52.txt AC 24 ms 6272 KB
1_53.txt AC 23 ms 6272 KB