Is the array the result of a traversal of a binary search tree

Title Description
Enter an integer array to determine whether the array is the result of a traversal of a binary search tree. If yes, output Yes, otherwise output No. Assume that any two numbers in the input array are different from each other.

Analysis:
The legal sequence of the BST sequence is that for a sequence S, the last element is x (that is, the root). If the sequence of the last element is T, then T satisfies: T can be divided into two segments, the previous (Left subtree) is less than x, the next segment (right subtree) is greater than x, and both segments (subtrees) are legal post-order sequences. Perfect recursive definition:).

在这里插入代码片
 public boolean VerifySquenceOfBST(int [] s) {
        if(s.length==0)
            return false;
	     return istree(s,0,s.length-1 ); 
	    }
	 public boolean istree(int []s,int a,int b) {
		 if(a>=b)return true;
		 int i=a,j;
		 for(;i<b;i++)
			 if(s[i]>s[b])
				 break;
		 j=i;
		 while(j<b)
			 {if(s[j]<s[b])
				 return false;
			 j++;}
		 return istree(s,a,i-1)&&istree(s,i,b-1);
		 
	 }