#include<stdio.h>
int pri[21];
void colm(int k,int n,int m,int i)
{

    for(int a=k;a<=n;a++)
    {
        pri[i]=a;
        if(i==m)
        {
            for(int b=1;b<=m;b++)
                printf("%d ",pri[b]);            
            printf("\n");
        }
        else
            colm(a+1,n,m,i+1);
    }
}   

int main(void)
{
    int n,m;
    scanf("%d %d",&n,&m);
    colm(1,n,m,1);
    return 0;
}

今天在上数学课的时候终于写出来，
晚上测试居然是wrong啊啊救命啊