牛客网-剑指office-二叉搜索树的后序遍历序列

题目：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。如果是则输出Yes,否则输出No。假设输入的数组的任意两个数字都互不相同。
思路：

class Solution {
public:
    bool VerifySquenceOfBST(vector<int> sequence) {
        if (sequence.empty()) return false;
		int length = sequence.size();
		int root = sequence[length - 1];
		int i = 0;
		for (; i < length - 1; ++i)
		{
			if (sequence[i] > root)
				break;
		}
		int j = i;
		for (; j < length - 1; ++j)
		{
			if (sequence[j] < root)
			{
				return false;
			}
		}
		bool left = true;
		if (i>0)
			left = VerifySquenceOfBST(vector<int>(sequence.begin(), sequence.begin() + i));
		bool right = true;
		if (j<length-1)
			right = VerifySquenceOfBST(vector<int>(sequence.begin()+j-1, sequence.end()));
		return left&&right;
    }
};