题解 | #栈的压入、弹出序列#

//借用辅助栈，注意：一定不能离开出栈序列和辅助栈顶元素，否则对于不符合出栈序列也可能导致辅助栈最后为空
class Solution {
public:

    bool IsPopOrder(vector<int>& pushV, vector<int>& popV) {
        stack<int> st;
        auto pushvit = pushV.begin();
        auto popvit = popV.begin();
        
        while(pushvit != pushV.end())
        {
            st.push(*pushvit);
            
            while(st.size()!=0 && *popvit == st.top())//用出栈的序列与辅助栈顶比较
            {
                st.pop();
                popvit++;
            }
           pushvit++;
        }
        return st.empty();
    }
    
};