Sorting a large list of test scores
This is a very easy question, assuming all scores are integers. 

Here is the simplest algorithm in plain words. We will initiate count, an integer array of 100 zeros. For each score s, we will add 1 to count[s]. To produce the wanted sorted scores, we will output count[1] 1s, count[2] 2s, ..., and finally count[100] 100s. 

This kind of sorting algorithm is called counting sort.

The case of more than $N&gt;10000$ test scores that are between 1 and 100 is a prime usage of counting sort. The time complexity is $O(N)$ and the space complexity  is bounded by some small constant multiple of 100.

You may want to check counting sort for more information.