class Solution {
public:
    bool isValid(string s) {


        unordered_map<char, char> my_map;
        my_map['('] = ')';
        my_map['{'] = '}';
        my_map['['] = ']';

        int sz = s.size();

        stack <char> my_stack;

        for (int i = 0 ; i < sz ; i++)
        {
            char c = s[i];
            if (my_map.find(c) != my_map.end())
            {
                my_stack.push(c);
            }
            else
            {
                if (my_stack.empty())
                    return false;

                char t = my_stack.top();
                if (my_map[t]==c)
                    my_stack.pop();
                else
                    return false;
            }
        }

        return my_stack.empty();

    }
};