#字符串
```cpp
class Solution
{
public:
int countAsterisks(string s)
{
stack<char> st;
auto ans = 0;
for (auto& ch : s)
{
if (st.empty())
{
if (ch == '|')st.push(ch);
if (ch == '*')ans++;
continue;
}
if (!st.empty() && ch == '|')st.pop();
}
return ans;
}
};
```