A collection of code samples to show off basic problem solving skills

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Happy Numbers
Description
A happy number is defined by the following process. Starting with any positive integer, 
replace the number by the sum of the squares of its digits, and repeat the process until 
the number equals 1 (where it will stay), or it loops endlessly in a cycle which does not 
include 1. Those numbers for which this process ends in 1 are happy numbers, while 
those that do not end in 1 are unhappy numbers.
Input sample
File containing a list of integers, one per line.
Sample
1
7
22
Output sample
If the number is happy, print out 1. It not, print out 0.
Sample
1
1
0
For the curious, here’s why 7 is a happy number: 7->49->97->130->10->1. Here’s why 
22 is NOT a happy number: 22->8->64->52->29->85->89->145->42->20->4->16->37-
>58->89 ...

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Longest Lines
Description
Write a program to read a multiple line file and output the ‘N’ longest lines.
Input sample
File containing a positive integer ‘N’ on the first line, followed by any number of strings, 
one per line.
Sample
2
Hello World
CBS Local
Quick Fox
A
San Francisco
Output sample
Print out the ‘N’ longest lines in decreasing order of length. Do NOT print out empty 
lines. Ensure that there are no trailing empty spaces on each line; these should not 
count toward a line’s length.
Sample
San Francisco
Hello World

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Number of Ones
Description
Write a program to determine the number of 1 bits in the internal representation of a 
given integer.
Input sample
File containing a list of integers, one per line.
Sample
10
22
56
Output sample
Print out the number of ones in the binary form of each number.
Sample
2
3
3

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Set Intersection
Description
You are given two ascending order sorted lists of numbers. The lists themselves are 
comma delimited and the two lists are semicolon delimited. Print out the intersection of 
the two sets.
Input sample
File containing two lists of ascending order sorted integers, comma delimited, one per 
line.
Sample
1,2,3,4;4,5,6
7,8,9;8,9,10,11,12
Output sample
Print out the ascending order sorted intersection of the two lists, one per line.
Sample
4
8,9

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Unique Elements
Description
You are given a sorted list of numbers with duplicates. Print out the sorted list with 
duplicates removed.
Input sample
File containing a list of sorted integers, comma delimited, one per line.
Sample
1,1,1,2,2,3,3,4,4
2,3,4,5,5
Output sample
Print out the sorted list with duplicates removed, one per line.
Sample
1,2,3,4
2,3,4,5