Parenthesis Checker

Given a string s, composed of different combinations of ‘(‘ , ‘)’, ‘{‘, ‘}’, ‘[‘, ‘]’, verify the validity of the arrangement.
An input string is valid if:

         1. Open brackets must be closed by the same type of brackets.
         2. Open brackets must be closed in the correct order.

Examples :

Input: s = "[{()}]"
Output: true
Explanation: All the brackets are well-formed.

Input: s = "[()()]{}"
Output: true
Explanation: All the brackets are well-formed.

Input: s = "([]"
Output: False
Explanation: The expression is not balanced as there is a missing ')' at the end.

Input: s = "([{]})"
Output: False
Explanation: The expression is not balanced as there is a closing ']' before the closing '}'.

Constraints:
1 ≤ s.size() ≤ 10⁶
s[i] ∈ {‘{‘, ‘}’, ‘(‘, ‘)’, ‘[‘, ‘]’}

class Solution {
  public:
    bool isBalanced(string& s) {

        stack<char> st;
        unordered_map<char,char> mp = {
            {'{','}'},
            {'(',')'},
            {'[',']'}
        };
        
        
        
        for( char c:s ) {
            
            if( mp.count(c) )
                st.push(c);
                
            else {
                
                if( st.empty() || mp[st.top()] != c ) 
                    return false;
                    
                st.pop();
            }
            
            
        }
        
        return st.empty();
        
    }
};