Valid Parentheses

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) {
        // Start typing your C/C++ solution below
        // DO NOT write int main() function
        stack<char> v;
        for(int ii = 0; ii < s.length(); ++ii){
            switch(s[ii]){
                case '{':
                case '[':
                case '(':
                    v.push(s[ii]);
                    break;
                case '}':
                case ']':
                case ')':
                    if (v.empty()) return false;
                    char c = v.top();//expect {[(
                    if (c+1 == s[ii] || c+2 == s[ii]) v.pop();//ASCII
                    else return false;
            }
        }
        return v.empty();
    }
};