剣指offer二叉探索木の後序遍歴シーケンス

class Solution {
public:
    bool VerifySquenceOfBST(vector<int> sequence) {
		int len = sequence.size();
        if(len == 0)
            return false;
        if(len == 1)
            return true;
        vector<int> left;
        vector<int> right;
        int middle = sequence[len - 1];
        int num = 0;
        while(sequence[num] < middle)
            left.push_back(sequence[num++]);
        while(num < len - 1)
            {
            if(sequence[num] < middle)
                return false;
            right.push_back(sequence[num++]);
        }
        if(left.size() == 0)
            return VerifySquenceOfBST(right);
        if(right.size() == 0)
            return VerifySquenceOfBST(left);
        return VerifySquenceOfBST(left) && VerifySquenceOfBST(right);
    }
};