Submission #1986576

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Source Code Expand

#include <bits/stdc++.h>
using namespace std;
static const int64_t INFL = 0x3F3F3F3F3F3F3F3FLL;
typedef int64_t ll;
typedef vector<ll> vll;
typedef vector<vll> vvll;
struct Solution {
    void solve(std::istream& in, std::ostream& out) {
        ll n;
        in >> n;
        vvll a(n, vll(n, INFL));
        ll ans = 0;
        for (int i = 0; i < n; i++) {
            ll t;
            in >> t;
            if (a[i][t - 1] != INFL) {
                ans++;
            }
            a[t - 1][i] = t;
        }
        out << ans << '\n';
    }
};
void solve(std::istream& in, std::ostream& out) {
    out << std::setprecision(12);
    Solution solution;
    solution.solve(in, out);
}
#include <fstream>
#include <iostream>
int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    istream& in = cin;
    ostream& out = cout;
    solve(in, out);
    return 0;
}

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