给定 pushed 和 popped 两个序列，每个序列中的值都不重复，只有当它们可能是在最初空栈上进行的推入 push 和弹出 pop 操作序列的结果时，返回 true；否则，返回 false 。
示例 1：
输入：pushed=[1,2,3,4,5],popped=[4,5,3,2,1]
输出：true
解释：我们可以按一下顺序执行：push(1),push(2),push(3),push(4),pop()->4,push(5),pop()->5,pop()->3,pop()->2,pop()->1
示例2:
输入：pushed=[1,2,3,4,5],popped=[4,3,5,1,2,]
输出：false
解释：1不能在2之前弹出
提示：
1、0<=pushed.length==poped.length<=1000
2、0<=pushed[i],poped[i]<1000
3、pushed是poped的排列
import java.util.Stack;
public class nfs {
public boolean validateStackSequences(int[] pushed, int[] popped) {
int N = pushed.length;
Stack stack =new Stack();
int j =0;
for (int x: pushed) {
stack.push(x);
while (!stack.isEmpty() && j < N && stack.peek() == popped[j]) {
stack.pop();
j++;
}
}
return j == N;
}
public static void main(String[] args){
int[] pushed = {1,2,3,4,5};
int[] popped = {4,3,5,1,2};
nfs nfv =new nfs();
System.out.print(nfv.validateStackSequences(pushed,popped));
}
}
