题解 | [Galadriel]#牛群的配对##C++#

class Solution {
public:
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     * 
     * @param s string字符串 
     * @return bool布尔型
     */
     //this solution is for C++
     //use the stack method
    bool isValidPairing(string s) {
        // write code here
        stack<char> stk;
        for(int i=0;i<s.size();i++){
            if(!stk.empty() && ((s[i]=='B' && stk.top()=='A')||(s[i]=='D' && stk.top()=='C'))){
                //match, out and next
                stk.pop();
            }else{
                //either stk is empty or its top ele is not matched
                //push into the stk
                stk.push(s[i]);
            }
        }
        //check the stk, if all matched, it should be empty
        if(stk.empty()) return true;
        return false;
    }
};