Valid Parentheses Given a string containing just the characters '(', ')', '{', '}', '[' and ']', determine if the input string is valid. The brackets must close in the correct order, "()" and "()[]{}" are all valid but "(]" and "([)]" are not.

ValidParen.cc

class Solution {
public:
    bool isValid(string s) {
        // IMPORTANT: Please reset any member data you declared, as
        // the same Solution instance will be reused for each test case.
        static unordered_map<char,char> bMap({ {'(',0}, {')',0}, {'[',1}, {']',1}, {'{',2}, {'}',2} });
        stack<char> ss;
        for(int i = 0; i<s.length(); ++i)
        {
            char c = s[i];
            if(c == '(' || c == '[' || c == '{')
                ss.push(c);
            else
            {
                if(ss.empty())
                    return false;
                else
                {
                    char t = ss.top();
                    if(bMap[t]!=bMap[c])
                        return false;
                    else
                        ss.pop();
                }
            }
        }
        
        if(!ss.empty())
            return false;
        else
            return true;
    }
};