Submission #891058

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Source Code Expand

#include <iostream>
#include <iosfwd>
#include <iomanip>
#include <cstdio>
#include <cstring>
#include <cstdlib>
#include <ctime>
#include <cmath>
#include <cassert>
#include <cctype>
#include <climits>
#include <vector>
#include <bitset>
#include <set>
#include <queue>
#include <stack>
#include <map>
#include <deque>
#include <string>
#include <list>
#include <iterator>
#include <sstream>
#include <complex>
#include <fstream>
#include <functional>
#include <numeric>
#include <utility>
#include <algorithm>
#include <assert.h>
#include <unordered_map>
using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef double ld;
typedef vector < long long > vll;
typedef pair <long long, long long> pll;
typedef pair <int, int> pii;
typedef vector < int > vii;
typedef complex < double > Point;

#define csl ios_base::sync_with_stdio(false); cin.tie(NULL)
#define mp make_pair
#define fst first
#define snd second

ll t, n, m, u, v, q, r, ql, qr, k, l, s, w, z, x, y, d, p, c, L, b;
const int N = 1e5 + 500;
const int LN = 21;
const long long mod = 1e9 + 7;
const long long INF = 1LL << 52LL;
string str;
int a[N];
int main() {
    csl;
    cin >> n;
    for (int i = 1; i <= n; ++i) {
        cin >> a[i];
    }
    int sol = 0;
    for (int i = 1; i <= n; ++i) {
        if (a[i] > i && a[a[i]] == i) sol++;
    }
    cout << sol << '\n';
    return 0;
}

Submission Info

Judge Result