剑指offer 21.栈的压入、弹出序列

 1 import java.util.Stack;
 2 public class Solution {
 3     //
 4     public boolean IsPopOrder(int [] pushA,int [] popA) {
 5         if(pushA.length == 0 || popA.length == 0)
 6             return false;
 7         Stack<Integer> stack = new Stack<>();
 8         int j = 0;
 9         for(int i = 0; i < pushA.length; i++){
10             stack.push(pushA[i]);
11             while(!stack.empty() && stack.peek() == popA[j]){
12                 stack.pop();
13                 j++;
14             }
15         }
16          return stack.empty();
17     }
18 }