Submission #69315149

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Source Code Expand

#pragma GCC optimize("Ofast")
#include <bits/stdc++.h>
using namespace std;
typedef long long int ll;
typedef unsigned long long int ull;

mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
ll myRand(ll B) { return (ull)rng() % B; }

int main() {
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    int n;
    cin >> n;
    vector<bool> ok(n + 1);
    vector<int> l(n);
    for (int i = 0; i < n; ++i) {
        cin >> l[i];
    }
    ok[0] = ok.back() = true;
    for (int i = 0; i < n; ++i) {
        if (ok[i] and !l[i]) {
            ok[i + 1] = true;
        }
    }
    for (int i = n - 1; i >= 0; --i) {
        if (ok[i + 1] and !l[i]) {
            ok[i] = true;
        }
    }
    int res = 0;
    for (auto &&i : ok) {
        if (!i) res += 1;
    }
    cout << res << endl;
}

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