#include <iostream>        #include <vector>        #include "iterator"        #include "algorithm"        #include "string"        #include "stdio.h"        using namespace std;        ostream_iterator<int> oi(cout,"");        int icount = 0;        void pailie(vector<int> vectNum,vector<int> &result,int start, int n)        {            if(start == n) {                //copy(result.begin(),result.end(),oi);                //cout<<" ";                icount++;                return;            };            int i;            for(i=0;i<vectNum.size();i++){                result[start] = vectNum[i];                vector<int> vectNew = vectNum;                vectNew.erase(vectNew.begin()+i);                pailie(vectNew,result,start+1,n);            }        }        void pailie(vector<int> vectNum,vector<int> &result, int n)        {            if(vectNum.size()<n) return;            pailie(vectNum,result, 0, n);        }                void main()        {            int a[9] = {1,2,3,4,5,6,7,8,9};            vector<int> vectNum(a,a+9);            int n=6;            vector<int> result(n);            pailie(vectNum, result,n);            cout<<endl<<icount<<endl;        }