Find Three Largest Numbers

Write a function that takes in an array of integers and returns a sorted 
array of the three largest integers in the input array. Note that 
the function should return duplicate integers if necessary; for example, 
it should return [10, 10, 12] for an input array of [10, 5, 9, 10, 12].

Sample input: [141, 1, 17, -7, -17, -27, 18, 541, 8 , 7, 7]
Sample output: [18, 141, 541]