題目描述

輸入一個整數陣列，判斷該陣列是不是某二叉搜尋樹的後序遍歷的結果。如果是則輸出Yes,否則輸出No。假設輸入的陣列的任意兩個數字都互不相同。
二叉搜尋樹是左子樹都比跟小，右子樹都比跟大
陣列的最後一個數字為root，然後一串比root小的為左子樹，一串比root大的為右子樹，當右子樹中有比root小的返回false，可以用遞迴的方式判斷左子樹和右子樹

class Solution:
    def VerifyCore(self, sequence, start, end):
        #print(start, end)
        if start ==
 
 end:
            return True
        root = sequence[end]
        for i in range(start, end + 1):
            if sequence[i] > root:
                break
        for j in range(i, end + 1):
            if sequence[j] < root:
                return False
        left = right = True
        if
 
 i > start:
            left = self.VerifyCore(sequence, start, i - 1)
        if i < end - 1:
            right = self.VerifyCore(sequence, i, end - 1)
        return left and right
    def VerifySquenceOfBST(self, sequence):
        # write code here
        if sequence == []:
            return
 
 False
        return self.VerifyCore(sequence, 0, len(sequence) - 1)
sequence = [7,4,6,5]
print(Solution().VerifySquenceOfBST(sequence))