Submission #1612195
Source Code Expand
//#include "IntMod.h"
//typedef IntMod<1000000007> MInt;
//#include "Union_Find.h"
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <iostream>
#include <string>
#include <vector>
#include <list>
#include <utility>
#include <algorithm>
#include <functional>
#include <cmath>
#include <stack>
#include <queue>
#include <set>
#include <map>
#include <iomanip>
#include <sstream>
#include <numeric>
#include <array>
#include <bitset>
using namespace std;
#define REP(i,a,n) for(int i = (a); i < (int)(n); ++i)
#define REPM(i,n,a) for(int i = ((n) - 1); i >= (a); --i)
#define EPS 0.0001
#define INF 0x3FFFFFFF
#define INFLL 0x3FFFFFFF3FFFFFFF
#define INFD 1.0e+308
#define FLOAT setprecision(16)
typedef long long LL;
typedef unsigned long long ULL;
typedef pair<LL, LL> PP;
template <class T, class U>
istream& operator>>(istream& ist, pair<T, U>& right) { return ist >> right.first >> right.second; }
template <class T, class U>
ostream& operator<<(ostream& ost, pair<T, U>& right) { return ost << right.first << ' ' << right.second; }
template <class T, class TCompatible, size_t N>
void Fill(T(&dest)[N], const TCompatible& val) { fill(begin(dest), end(dest), val); }
template <class T, class TCompatible, size_t M, size_t N>
void Fill(T(&dest)[M][N], const TCompatible& val) { for (int i = 0; i < M; ++i) Fill(dest[i], val); }
// all_of
#if 1
#include <unordered_set>
#include <unordered_map>
template<typename T>
using PriorityQ = priority_queue<T, vector<T>, greater<T> >; // コスト小を優先
#endif
int N;
int a[100000];
int main() {
cin >> N;
REP(i, 0, N) {
cin >> a[i];
a[i]--;
}
int sum = 0;
REP(i, 0, N) {
if (a[a[i]] == i) ++sum;
}
cout << sum / 2 << endl;
return 0;
}
Submission Info
Submission Time |
|
Task |
B - Friendly Rabbits |
User |
Aquarius |
Language |
C++14 (GCC 5.4.1) |
Score |
200 |
Code Size |
1793 Byte |
Status |
AC |
Exec Time |
37 ms |
Memory |
640 KB |
Judge Result
Set Name |
Sample |
All |
Score / Max Score |
0 / 0 |
200 / 200 |
Status |
|
|
Set Name |
Test Cases |
Sample |
0_00.txt, 0_01.txt, 0_02.txt |
All |
0_00.txt, 0_01.txt, 0_02.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 |
Case Name |
Status |
Exec Time |
Memory |
0_00.txt |
AC |
1 ms |
256 KB |
0_01.txt |
AC |
1 ms |
256 KB |
0_02.txt |
AC |
1 ms |
256 KB |
1_00.txt |
AC |
1 ms |
256 KB |
1_01.txt |
AC |
36 ms |
640 KB |
1_02.txt |
AC |
36 ms |
640 KB |
1_03.txt |
AC |
36 ms |
640 KB |
1_04.txt |
AC |
36 ms |
640 KB |
1_05.txt |
AC |
37 ms |
640 KB |
1_06.txt |
AC |
36 ms |
640 KB |
1_07.txt |
AC |
36 ms |
640 KB |
1_08.txt |
AC |
14 ms |
384 KB |
1_09.txt |
AC |
30 ms |
512 KB |
1_10.txt |
AC |
26 ms |
512 KB |
1_11.txt |
AC |
7 ms |
256 KB |