力扣题解(栈)

20. 有效的括号

class Solution {
public:
    bool isValid(string s) {
        stack<char> stack;
        for (int i = 0; i < s.size(); i++) {
            switch(s[i]) {
                case '(':
                    stack.push(')');
                    break;
                case '[':
                    stack.push(']');
                    break;
                case '{':
                    stack.push('}');
                    break;
                default:
                    if(stack.size() == 0 || s[i] != stack.top())
                        return false;
                    stack.pop();
            }
        }
        if (stack.size() == 0)
            return true;
        else
            return false;
    }
};