样例

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

    }
};