Our planet is warming up at an alarming pace, and Santa is fervently looking for ways to cut down on CO2 emissions. The red man is acutely aware of the carbon footprint galloping around the world at turbo speed generates, and has made it his mission to find a more sustainable way to bring delight and joy to families around the world.
At your disposal, you have Santa’s most highly guarded trade secret, the Nice List. The coveted List details which present shall be given to which child. Here’s the kicker: Santa’s sleigh can only carry 10 metric tons (10,000kg) at a time, and for each trip Santa makes, you'll need to tell him which items to pack.
You can download the list here. In the file, you'll find the wish of each child. Each row contains one wish. For privacy purposes, we've left out the names of the children: instead, their files include a numerical ID, their coordinates on Earth, and the weight of their present in grams. Your job is to find the most optimal routes to deliver all the presents. Santa starts at Korvatunturi, Finland (68.073611N 29.315278E) and, based on your list, flies directly from one coordinate to another until all presents are delivered, and then returns to Korvatunturi. The shorter the overall length of the trip, the less emissions there will be. For the purposes of this task, we assume Earth to be a sphere with radius of 6,378km.
To submit your solution, upload a .csv file below. You are welcome to upload multiple solutions to improve your score. Each row should contain a single gift run starting from Korvatunturi, listing all the children who Santa will visit on the run, their IDs separated with a semicolon. See example file here. You cannot exceed the capacity of the sleigh on a single run. Once you've sent over your solution, we will tally up the total distance covered for all rows. Whoever delivers all the presents while covering the least distance, wins!