leedcode - 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.

bool isValid(string s) {
        left = { '(', '{', '[' };
	vector<char> right = { ')', '}', ']' };

	stack<char> sc;

	for (int i = 0; i < s.length(); i++) {
		if (std::find(left.begin(), left.end(), s[i] ) != left.end()) {	sc.push(s[i]);	continue;}
                vector<char>::iterator it = std::find(right.begin(), right.end(), s[i]);
                if( it == right.end()) { continue;}
		if (sc.empty() || sc.top() != left[it - right.begin()]) { return false; }
			sc.pop();
	}
	return sc.empty();
 }

下面这种代码或许更加简洁：

 bool isValid(string s) {
        stack<char> sc;
        for( char c : s) {
            if( c == '[' || c == '(' || c == '{') { sc.push(c);continue;}
            else if( c == ']' || c == ')' || c == '}') {
                if(sc.empty()) return false;
                if( c == ']' && sc.top() != '[') return false;
                if( c == ')' && sc.top() != '(') return false;
                if( c == '}' && sc.top() != '{') return false;
                sc.pop();
            }
        }
        return sc.empty();
    }