组合数算法 C(n,m)(n=m)

#include<iostream>using namespace std;int a[]={1,2,3,4,5,6,7,8,9},b[10],n=9,m=5,counter=0;void output(){for(int i=0;i<m;i++)cout<<b[i]<<" ";cout<<endl;}void dfs(int step,int index){if(step==m)//boundary condition{output();counter++;return ;}for(int i=index;i<n;i++){b[step]=a[i];dfs(step+1,i+1);}}int main(){dfs(0,0);cout<<counter<<endl;return 0;}

，夫妇一条心，泥土变黄金。