nums in non-decreasing order.i starting at index 0 and j starting at index len(nums) // 2.count to keep track of the number of marked indices.i and j are within the bounds of the array:
a. If 2 * nums[i] <= nums[j], mark both indices by incrementing count by 2, and move both pointers to the next index.
b. If the condition is not met, only move the second pointer j to the next index.count as the maximum number of marked indices.