LintCode: Valid Parentheses

C++

stack<char|int|string>, push(), pop(), top(), empty(), size()

 class Solution {
 public:
     /**
      * @param s A string
      * @return whether the string is a valid parentheses
      */
     bool isValidParentheses(string& s) {
         // Write your code here
         stack<char> sta;
         for (int i = ; i < s.size(); i++) {
             if (s[i] == '(' || s[i] == '{' || s[i] == '[') {
                 sta.push(s[i]);
                 continue;
             }
             char top = sta.top();
             sta.pop();
             if (s[i] == ')' && top != '(') return false;
             if (s[i] == ']' && top != '[') return false;
             if (s[i] == '}' && top != '{') return false;
         }
         return sta.empty();
     }
 };