문제
풀이
#include <iostream>
#include <vector>
using namespace std;
void solve(void) {
int n; cin >> n;
vector<int> v(n);
for (int i=0; i<n; i++) cin >> v[i];
int ans = 0, cur = 0;
for (int i=0; i<n; i++) {
if (v[i] != cur) continue;
ans++;
cur = (cur+1) % 3;
}
cout << ans;
}
int main(void) {
ios::sync_with_stdio(false);
cin.tie(nullptr);
solve();
return 0;
}