#栈与队列 #有效的括号

valid-parentheses.cpp

class Solution {
public:
    bool isValid(string s) {
        stack<int> check;
        map<char, char> bracket_map;
        bracket_map['('] = ')';
        bracket_map['['] = ']';
        bracket_map['{'] = '}';
        for (int i = 0; i < s.size(); ++i) {
            if (s[i] == '(' || s[i] == '[' || s[i] == '{')
                check.push(s[i]);
            else {
                if (check.empty())
                    return false;
                if (bracket_map[check.top()] == s[i])
                    check.pop();
                else 
                    return false;
            }
        }
        if (check.empty())
            return true;
        else 
            return false;
    }
};