面试题24 二叉搜索树的后序遍历序列

题目描述

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。

class Solution {
public:
    bool VerifySquenceOfBST(vector<int> sequence) {
        if (sequence.size() == 0){
            return false;
        }
        if (sequence.size() == 1){
            return true;
        }
        int i = sequence.size()-1, k;
        vector<int> v1, v2;
        for (k = 0; k < i; k++){
            if (sequence[k] < sequence[i]){
                v1.push_back(sequence[k]);
            }
            else
                break;
        }
        for (int j = k; j < i; j++){
            if (sequence[j] > sequence[i]){
                v2.push_back(sequence[j]);
            }
            else
                return false;
        }
        bool left = true, right = true;
        if (v1.size() >= 1)
            left = VerifySquenceOfBST(v1);
        if (v2.size() >= 1)
            right = VerifySquenceOfBST(v2);
        return left && right;
    }
};