剑指Offer之栈的压入、弹出序列

 1 import java.util.ArrayList;
 2 
 3 import java.util.Stack;
 4 
 5 public class Solution {
 6     public boolean IsPopOrder(int [] pushA,int [] popA) {
 7       if(pushA==null||popA==null)
 8               return false;
 9           Stack<Integer> stack=new Stack<>();
10           int index=0;
11           for(int i=0;i<pushA.length;i++) {
12               stack.push(pushA[i]);
13               while(!stack.isEmpty()&&stack.peek()==popA[index]) {
14                   stack.pop();
15                   index++;
16               }
17           }
18           return stack.isEmpty();
19     }
20 }