Hi, here's your problem today. This problem was recently asked by Uber:

Given a number of integers, combine them so it would create the largest number.

Example:
Input:  [17, 7, 2, 45, 72]
Output:  77245217
<pre lang=py>
def largestNum(nums):
  # Fill this in.

print largestNum([17, 7, 2, 45, 72])
# 77245217
</pre>