Java: Calculating binomial coefficient

Question

I have the following programm calculating the binomial coefficient of two integers. But I want to change the programm, that it calculates and saves only the necessary coeffi

Answer 1

You don't say which coefficients youi need. If you need C(N,n) for some fixed N, you could translate the C code below, which uses a one dimensional array. After the call, C[n] will hold the binomial coefficient C(N,n) for 0<=m<=N, as long as N is at most 66 -- if you need bigger N you will need to use an integral type with more bits.

static  int64_t*    pascals_triangle( int N)
{
int n,k;
int64_t*    C = calloc( N+1, sizeof *C);
    for( n=0; n<=N; ++n)
    {   C[n] = 1;
        k = n;
        while( --k>0)
        {   C[k] += C[k-1];
        }
    }
    return C;
}