面试题31. 栈的压入、弹出序列

题目：

 

 

解答：

 

 

class Solution {
public:
    bool validateStackSequences(vector<int>& pushed, vector<int>& popped) 
    {
        stack<int> st;
        int n = popped.size();
        int j = 0;
        for (int i = 0; i < pushed.size(); ++i)\
        {
            st.push(pushed[i]);
            while(!st.empty() && j < n && st.top() == popped[j])
            {
                st.pop();
                ++j;
            }
        }
        return st.empty();
    }
};