leetcode

0 class Solution {

1 public:

2 bool validateStackSequences(vector<int> &pushed, vector<int> &popped) {

3 int n = pushed.size(), m = popped.size();

4 int i = 0, j = 0;

5 stack<int> st;

6

7 while (i < n || j < m) {

8 if (st.empty()) {

9 if (i < n)

10 st.push(pushed[i++]);

11 else

12 return false;

13 } else {

14 if (st.top() == popped[j])

15 st.pop(), j++;

16 else if (i < n)

17 st.push(pushed[i++]);

18 else

19 return false;

20 }

21 }

22

23 return true;

24 }

25 };