Question

The question is – how many three numbers exits (of the provided) that sum to zero?

I’m wondering, how to implement this brute force method (below) in ruby? The main aspect of this is : what is better to use in a place of for loop? times?
a – is array of integers, the data that’s provided

int N = a.length;
int count = 0;
for(int i = 0; i<N; i++)
  for(int j = i+1; j<N; j++)
    for(int k = j+ 1; k<N; k++)
      if (a[i] + a[j] + a[k] == 0 )
        count++;
return count;

Answer 1

How about:

a.combination(3).count{|x,y,z| x+y+z==0}

But I don’t get the connection with Rails here 😉