题解 | #栈的压入、弹出序列#

[1,2,3,4,5],[4,3,5,1,2]
思路是维护一个栈，查看栈顶元素跟弹出序列是否一致，如果一致就出栈，否则就继续入栈。

import java.util.ArrayList;
import java.util.Stack;

public class Solution {
    public boolean IsPopOrder(int [] pushA,int [] popA) {
        Stack<Integer> stack = new Stack();
        int j = 0;

        for (int i = 0; i < pushA.length; i++) {
            stack.push(pushA[i]);
            while (!stack.isEmpty() && j < popA.length && stack.peek() == popA[j]) {
                stack.pop();
                j++;
            }
        }

        return stack.isEmpty() && j == popA.length;
    }
}