balanced brackets hackerrank solution in cpp

1#include <iostream>
2#include <algorithm>
3#include <unordered_map>
4#include <stack>
5using namespace std;
6string isBalanced(string s){
7    stack <char> st;
8    for(auto c:s){
9        switch (c){
10            case '(':
11            case '{':
12            case '[':
13                  st.push(c);
14                   break;
15            case '}':
16                if(st.empty() || st.top()!='{' )
17                    return "NO";
18                st.pop();
19                break;
20            case ']':
21                if(st.empty() || st.top()!='[')
22                    return "NO";
23                st.pop();
24                break;
25            case ')':
26                if(st.empty() || st.top()!='(')
27                    return "NO";
28                st.pop();
29                break;
30            default: break;
31        }
32    }
33    return st.empty() ? "YES":"NO";
34}
35
36int main(){
37    int t;
38    cin >> t;
39    for(int a0 = 0; a0 < t; a0++){
40        string s;
41        cin >> s;
42        cout << isBalanced(s) << endl;
43    }
44    return 0;
45}
46