如果,下一个弹出的数字不在栈顶,我们把压榨你序列中还没有入栈的数字压入辅助栈,直到把下一个需要弹出的数字入栈顶为止
如果数字都压入栈了还是没有找到,那个序列就不是一个弹出序列
public class T22_StackPushPopOrder { @Test public void test1() { int[] pushA = {1, 2, 3, 4, 5}; int[] popA = {4, 5, 3, 2, 1}; System.out.println(IsPopOrder(pushA, popA)); int[] popA1 = {4, 3, 5, 1, 2}; System.out.println(IsPopOrder(pushA, popA1)); } public boolean IsPopOrder(int [] pushA,int [] popA) { if (pushA.length == 0) { return false; } Stack<Integer> stack = new Stack<>(); for (int i = 0, j = 0; i <popA.length; i++) { stack.push(pushA[i]); while (j < popA.length && stack.peek() == popA[j]) { stack.pop(); j++; } } return stack.isEmpty(); } }