Submission #73607018

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Source Code Expand

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

mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());

#define all(x) (x).begin(), (x).end()
#define vi vector<int>
typedef long long ll;
typedef unsigned long long ull;
typedef long double lld;
#define mp make_pair
#define A first
#define B second

#ifdef LOCAL
#include "debug.h"
#else
#define debug(x)
#endif

#define int long long
#define MOD 1000000007LL


void solve() {
    int n; cin >> n;
    vi arr(n * 2 + 1);
    for (int i = 1; i <= n * 2; i++) cin >> arr[i];

    if (n < 3) {
        cout << 0 << "\n";
        return;
    }
    int ans = 0;
    for (int i = 1; i <= (n * 2 - 2); i++) {
        if (arr[i] == arr[i + 2]) ans++;
    }
    cout << ans << "\n";
}


signed main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL); cout.tie(NULL);

#ifdef LOCAL
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
    freopen("error.txt", "w", stderr);
#endif
    int tt = 1;
    //cin >> tt;
    auto start = std::chrono::high_resolution_clock::now();
    while (tt--) solve();
    auto stop = std::chrono::high_resolution_clock::now();
    auto duration = std::chrono::duration_cast<std::chrono::microseconds>(stop - start);
    cerr << duration.count() << endl;
    return 0;
}

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