Let’s pretend four travelers with different weights arrive at river on a dark night. There’s only one flashlight and only two travelers can cross via the single boat at a time, and the time that it takes to cross the river is the greater weight (e.g. if two passengers have weights of 5 & 20, it takes 20 minutes for the two people to cross one direction and 5 for the person with the flashlight to return for additional passengers). If the four travelers have weights of {1, 2, 5, 10}, what’s the configuration that will get everyone across in the least amount of time?
