combnation

1 から n1 + n2 までの n1 + n2 個の数字から n1 個を取り出す組み合わせ

#define first(n) ( (unsigned int)( ( 1U<<(n) ) - 1U ) )
void comb1(int n1,int n2)
{
    int i,j,k,m[101];
    unsigned int x,s;
    unsigned int smallest,ripple,new_smallest,ones;

    i=1; x=first(n1);
    while( ! (x & ~first(n1+n2)) ) {
        s=x; k=1;
        for( j=1;j<=n1+n2;j++ ) {
            if( s & 1 ) {
                m[k]=j;
                k++;
            }
            s >>= 1;
        }
        for(k=1;k<=n1;k++) printf(" %2d",m[k]);
        printf("\n");
        smallest = x & -x;
        ripple = x + smallest;
        new_smallest = ripple & -ripple;
        ones = ( ( new_smallest/smallest ) >> 1 ) - 1;
        x= ripple | ones;
        i++;
    }
}

aaa