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