class Solution { public: bool isValid(string s){ stack<char>S;for(auto c:s) if(S.empty())S.push(c); else{char C=S.top(); if((C=='('&&c==')')||(C=='['&&c==']')|| (C=='{'&&c=='}'))S.pop(); else S.push(c); } return S.empty(); } };
给出一个简洁的题解