栈的压入弹出序列

题目描述：
输入两个整数序列，第一个序列表示栈的压入顺序，请判断第二个序列是否为该栈的弹出顺序。假设压入栈的所有数字均不相等。例如序列1,2,3,4,5是某栈的压入顺序，序列4，5,3,2,1是该压栈序列对应的一个弹出序列，但4,3,5,1,2就不可能是该压栈序列的弹出序列。（注意：这两个序列的长度是相等的）

#include "stdafx.h"  #include <iostream>  #include <stack>  using namespace std;  bool IsPopOrder(int *pPush, int *pPop, int nLength)  {     if (pPush == NULL || pPop == NULL || nLength <= 0)     {         return false;     }     stack<int> s;     s.push(pPush[0]);     int nPop_index = 0;     int nPush_index = 1;     while (nPop_index < nLength)     {         while (s.top() != pPop[nPop_index] && nPush_index < nLength)         {             s.push(pPush[nPush_index]);             nPush_index++;         }         if (s.top() == pPop[nPop_index])         {             s.pop();             nPop_index++;         }         else         {             return false;         }            }     return true;  }  int _tmain(int argc, _TCHAR* argv[])  {      int nPush[5] = {1,2,3,4,5};       int nPop1[5] = {4,5,3,2,1};      int nPop2[5] = {4,3,5,1,2};      int nPop3[5] = {5,4,3,2,1};      int nPop4[5] = {4,5,2,3,1};      cout << IsPopOrder(nPush, nPop1, 5) << endl;      cout << IsPopOrder(nPush, nPop2, 5) << endl;      cout << IsPopOrder(nPush, nPop3, 5) << endl;      cout << IsPopOrder(nPush, nPop4, 5) << endl;      system("pause");      return 0;  }  

另一个思路：

class Solution {public:    bool IsPopOrder(vector<int> pushV,vector<int> popV) {        vector<int>temp;         int j = 0;        for(int i=0;i<pushV.size();)         {            temp.push_back(pushV[i++]);            while(j<popV.size()&&temp[temp.size()-1]==popV[j])            {                temp.pop_back();                ++j;            }         }       return temp.empty();    }};