0~9十个数字能组成多少个各位数均不同的三位数

0~9十个数字能组成多少个各位数均不同的三位数

#include <iostream>
#include <cmath>
#include <string.h>
#include <algorithm>
#include <map>using namespace std;void funcP21_3(){int A[10]={1,2,3};sort(A,A+10);int cnt=0;cout<<"[";map<int,int> index;do{int num=0;for(int i=0;i<=9;i++){if(A[0]==3)break;if(A[i]!=0)num+=i*pow(10,A[i]-1);}if(A[0]==3)continue;if(index[num]!=1){index[num]=1;cnt++;cout<<num<<",";}}while(next_permutation(A,A+10));cout<<"]\n"<<cnt<<endl;
}int main()
{funcP21_3();cout << "\nHello World!" << endl;return 0;
}