LeetCode: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.

 

 

class Solution {
public:
    bool isValid(string s) {
        stack<char> cstack;
        string left="({[";
        string right=")}]";
        
        for(auto c:s)
        {
            if(left.find(c)!=s.npos)
                cstack.push(c);
            else if(cstack.empty()||cstack.top()!=left[right.find(c)])
                return false;
            else
                cstack.pop();
        }
    
        return cstack.empty();
        
    }
};