# CS210 Algorithms & Data Structures 1

1.
Write a Java program that outputs the quantity
of prime numbers

under an input number n which is inputted by the user. For

example, if the user inputs 10, then the program outputs 4.

Provide comments which explain how the algorithm works.

[20 marks]

2.  Write a Java
program that prints the integers from 1 to 100. But

for multiples of three print "Fizz" instead of the
number and for

the multiples of five print "Buzz". For numbers
which are

multiples of both three and five print "FizzBuzz".
Provide

comments which explain how the algorithm works.

[20 marks]

3 . Write a Java method that takes in a reference to the

double-ended doubly-linked list and reverses it. Provide

comments which explain how the algorithm works.

[20 marks]

4 . Write a Java method that takes in an array of strings
and sorts

them by the number of unique characters in each string.
Provide

comments which explain how the algorithm works.

[20 marks]

5 . Write a Java program that takes in an array of ints and
finds the

maximum contiguous subsequence sum, given an input length

n. For example, for the following array, where n = 3 and the

array is {-5 -1 2 -3 0 -3 3} the best possible sum of at
least length

3 would be 0, where the subsequence is the last three
elements

(0, -3, 3). Provide comments which explain how the algorithm

works.