剑指offer 栈的压入、弹出序列

class Solution {
public:
    bool IsPopOrder(vector<int> pushV,vector<int> popV) {
        if(pushV.size() == 0){
            return false;
        }
        stack<int> s;
        for(int i = 0,j = 0;i < pushV.size();++i){
            s.push(pushV[i]);
            while(j < popV.size() && s.top() == popV[j] && !s.empty()){
                s.pop();
                ++j;
            }
        }
        return s.empty();
    }
};