The valid parentheses__ algorithm for Leetcode algorithm problem

Problem Description:

Given A string containing just the characters ' (', ') ', ' {', '} ', ' [' and '] ', determine if the input string is valid.

The brackets must the correct order, "()" and "() []{} ' are all valid but ' (]" and "([)]" are not.

Ideas for solving problems:

Typical use of the pressure stack to solve the problem.

Class Solution {Public:bool isValid (string s) {stack<char> charstack;

        size_t i = 0;
            while (I!= s.length ()) {char c = s[i];
            if (c!= ') ' && C!= '} ' && C!= '] {Charstack.push (c);

                else {if (charstack.size () = = 0) return false;
                char pre = Charstack.top (); Switch (c) {case ') ': if (pre = = ' (') charstack.
                    Pop ();
                    else return false;

                Break
                    Case '} ': if (pre = = ' {') charstack.pop ();
                    else return false;

                Break
           Case '] ': if (pre = = ' [') Charstack.pop ();         else return false;
                Break
        }} ++i;
        } if (charstack.size () = = 0) return true;
    else return false; }
};