数据结构-二叉搜索树的后序遍历序列

/*
剑指offer面试题24
*/
#include <iostream>

using namespace std;

bool IsPostTree(int* a,int length){
    if(length <= 0){
        return false;
    }

    int root = *(a+length-1);

    int i=0;
    for(;i<length-1;i++){
        if(a[i] > root){
            break;
        }
    }

    int j=0;
    for(j=i;j<length-1;j++){
        if(a[j] < root){
            return false;
        }
    }

    bool left = true;
    if(i>0){
        left = IsPostTree(a,i);
    }

    bool right = true;
    if(j<length-1){
        right = IsPostTree(a+i,length-i-1);
    }

    return (left && right);
}

int main()
{
    int length,n;

    cin >> length;

    int a[length];

    if(length > 0){
        for(int i=0;i<length;i++){
            cin >> n;
            a[i] = n;
        }
    }

    bool result = IsPostTree(a,length);

    cout << result;

    return 0;
}