https://www.nowcoder.com/practice/d77d11405cc7470d82554cb392585106

辅助栈

image.png

  1. public boolean IsPopOrder(int[] pushA, int[] popA) {
  2.     int n = pushA.length;
  3.     //辅助栈
  4.     Stack<Integer> s = new Stack<>();
  6.     //遍历入栈的下标
  7.     int i = 0;
  8.     //遍历出栈的数组
  9.     for (int j = 0; j < n; j++) {
  10.         //入栈：栈为空或者栈顶不等于出栈数组
  11.         while (i < n && (s.isEmpty() || s.peek() != popA[j])) {
  12.             s.push(pushA[i]);
  13.             i++;
  14.         }
  16.         //栈顶等于出栈数组
  17.         if (s.peek() == popA[j]) {
  18.             s.pop();
  19.         } else {
  20.             //不匹配序列
  21.             return false;
  22.         }
  23.     }
  24.     return true;
  26. }