#include <bits/stdc++.h>
using namespace std;
#define int long long
#define endl '\n'
void solve(){
int n; cin >> n;
vector<int> a(n);
for (auto &i : a) cin >> i;
a.push_back(1);
bool b = 0;
int ans = 0;
for (int i = 0; i < n; i++){
if (a[i] == 1) b = 1;
if (a[i] == -1 && b){
if (a[i + 1] == -1) {ans++; i++;}
else {
cout << -1 << endl;
return;
}
}
}
cout << ans << endl;
}
signed main(){
ios::sync_with_stdio(0);
cin.tie(0);
int tc = 1;
// cin >> tc;
while (tc--){
solve();
}
}
| # | Verdict | Execution time | Memory | Grader output |
|---|
| Fetching results... |
| # | Verdict | Execution time | Memory | Grader output |
|---|
| Fetching results... |
| # | Verdict | Execution time | Memory | Grader output |
|---|
| Fetching results... |
| # | Verdict | Execution time | Memory | Grader output |
|---|
| Fetching results... |
| # | Verdict | Execution time | Memory | Grader output |
|---|
| Fetching results... |
| # | Verdict | Execution time | Memory | Grader output |
|---|
| Fetching results... |
| # | Verdict | Execution time | Memory | Grader output |
|---|
| Fetching results... |
| # | Verdict | Execution time | Memory | Grader output |
|---|
| Fetching results... |