This was fun
There are simpler approaches using a temporary array, but makes a nice challenge trying to do it without (it's possible that it would end up faster too, but how big an array we'd need in order to notice… I'm not sure).Have a gander and see what you think:
// need to expand the array size by a variable amount, so that its original elements are repeated evenly // original array [A,B,C], expanded by 4 should return: [A,A,A,B,B,C,C] i[]@array = {1,2,3,4,5}; int expand_count = chi("expand"); int input_len = len(i[]@array); int output_len = input_len + expand_count; // vex may well optimize this for us, but still a good habit to // resize an array only once if we know the desired array size in advance // rather than call append() or insert() inside a loop resize(i[]@array, output_len); for(int i=input_len; i>0; i--) { // we want to write out the i-th input value to the highest 'unwritten' // output index until i doesn't fit in our unwritten range int inner_loop = output_len/i; for(int j=0; j<inner_loop; j++) { // write the i-th input value to the end of the unwritten portion // of the output array i[]@array[output_len-1] = i[]@array[i-1]; // reduce the size of the unwritten portion output_len--; } }
I haven't had a change to properly untangle what was up with your original code, but my first guess is that you were getting bitten by the data dependencies between ‘count’ and 'i@array' inside the loop.
Cheers!
