20.有效的括号

🥛stack

class Solution {
public:
    bool isValid(string s) {
        stack<char> stk;
        for(auto c : s) {
            if(!stk.size()) {
                stk.push(c);
                continue;
            }
            int t = stk.top();
            if(t == '{' && c == '}' ||
            t == '(' && c == ')' ||
            t == '[' && c == ']')
            {
                stk.pop();
                continue;
            }
            stk.push(c);
        }
        return stk.size() == 0;
    }
};

Accepted

76/76 cases passed (4 ms)

Your runtime beats 69.91 % of cpp submissions

Your memory usage beats 5.33 % of cpp submissions (8.7 MB)