[剑指offer][面试题24]二叉搜索树的后序遍历序列

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。如果是则返回true，否则返回false。假设输入的数组的任意两个数字都互不相同。例如输入数组{5,7,6,9,11,10,8}，则返回true，如果输入的数组是{7,4,6,5}，则返回false。

#include <iostream>
#include <stack>
using namespace std;

bool isPostOrderOfBST(int *pOrder, int iLength)
{
if (pOrder==NULL){
return false;
}

int iValRoot = pOrder[iLength-1];
int iLenLeft = -1;
int iLenRight= -1;

while (pOrder[iLenLeft+1]<iValRoot){
iLenLeft++;
}
iLenLeft++;
iLenRight = iLength-1-iLenLeft;

for (int i=iLenLeft; i<iLength; i++){
if (pOrder[i]<iValRoot-1){
return false;
}
}

if (iLenLeft==0 && iLenRight==0){
return true;
}
else if(iLenLeft==0 || iLenRight==0){
return isPostOrderOfBST(pOrder, iLength-1);
}
else{
return isPostOrderOfBST(pOrder, iLenLeft) && isPostOrderOfBST(pOrder+iLenLeft, iLenRight);
}
}

int main()
{
int pPostOrder0[] = {5,7,6,9,11,10,8};
int pPostOrder1[] = {5,7,9,6,11,10,8};

cout<<isPostOrderOfBST(pPostOrder0, 7)<<endl;
cout<<isPostOrderOfBST(pPostOrder1, 7)<<endl;
}