Java实现：输入一个整数数组，判断该数组是不是某二叉搜索树的后序遍历的结果。

import java.util.Arrays;
import java.util.Scanner;

public class Tree4 {

static boolean verifysequence(int[] sequence){
int length=sequence.length;
int root=sequence[length-1];
if(sequence==null||length <=0)
return false;

//在二叉搜索树中左子树的节点小于根节点
int i=0;
for (; i < length-1; i++) {
if(sequence[i]>root)
break;
}
//在二叉搜索树中右子树的节点大于根节点
int j=i;
for(;j<length-1;j++){
if(sequence[j]<root)
return false;
}
//判断左子树是不是二叉搜索树
boolean left=true;
if(i>0)
left=verifysequence(Arrays.copyOfRange(sequence, 0, i));

//判断右子树是不是二叉树
boolean right=true;
if(i<length-1)
right=verifysequence(Arrays.copyOfRange(sequence, i, sequence.length-1));

return(left&&right);
}

public static void main(String[] args) {
Scanner sc=new Scanner(System.in);
String[] sr=sc.nextLine().split(" ");
int[] arr=new int[sr.length];
for (int i = 0; i < sr.length; i++) {
arr[i]=Integer.parseInt(sr[i]);
}
System.out.println(verifysequence(arr)?"true":"false");
sc.close();

}

}