Auto comment: topic has been updated by KKOrange (previous revision, new revision, compare).

All numbers can be written in the form n*2^k, where n is odd. For every number to be the same, they clearly need to have the same value of n. The only way to change the value of n is to divide by two. So this is the only operation we should do until all numbers have the same value of n. Once this is done, we need to make all the k the same. This is done optimally by finding the median number and making everything equal to that. So anything larger than the median, we divide by two until it is the same as the median, and multiply by two for anything smaller than the median.

When we make all n the same, clearly all numbers are decreasing. When we make all k the same, clearly all numbers are moving towards the median (which is less than the max). Hence, we never need to exceed the maximum number.