list_comp.py

"""

Let's learn about list comprehensions! You are given three integers X,Y and Z representing the dimensions of a cuboid. You have to print a list of all possible coordinates on a 3D grid where the sum of Xi + Yi + Zi is not equal to N. If X=2, the possible values of Xi can be 0, 1 and 2. The same applies to Y and Z.

Input Format

Four integers X,Y,Z and N each on four separate lines, respectively.

Output Format

Print the list in lexicographic increasing order.

Sample Input

1
1
1
2
Sample Output

[[0, 0, 0], [0, 0, 1], [0, 1, 0], [1, 0, 0], [1, 1, 1]]
Concept

You have already used lists in previous hacks. List comprehensions are an elegant way to build a list without having to use different for loops to append values one by one. These examples might help.

The simplest form of a list comprehension is: 

[ expression-involving-loop-variable for loop-variable in sequence ] 

This will step over every element in a sequence, successively setting the loop-variable equal to every element one at a time. It will then build up a list by evaluating the expression-involving-loop-variable for each one. This eliminates the need to use lambda forms and generally produces a much more readable code than using map() and a more compact code than using a for loop.

>> ListOfNumbers = [ x for x in range(10) ] # List of integers from 0 to 9
>> ListOfNumbers
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
List comprehensions can be nested where they take the following form: 

[ expression-involving-loop-variables for outer-loop-variable in outer-sequence for inner-loop-variable in inner-sequence ] 

This is equivalent to writing: 

results = []
for outer_loop_variable in outer_sequence:
    for inner_loop_variable in inner_sequence:
        results.append( expression_involving_loop_variables )

The final form of list comprehension involves creating a list and filtering it similar to using the filter() method. The filtering form of list comprehension takes the following form: 

[ expression-involving-loop-variable for loop-variable in sequence if boolean-expression-involving-loop-variable ] 

This form is similar to the simple form of list comprehension, but it evaluates boolean-expression-involving-loop-variable for every item. It also only keeps those members for which the boolean expression is True.

>> ListOfThreeMultiples = [x for x in range(10) if x % 3 == 0] # Multiples of 3 below 10
>> ListOfThreeMultiples
[0, 3, 6, 9]

"""

x,y,z,n = ( input() for _ in xrange(4))
print  [ [a,b,c] for a in range(x+1) for b in range(y+1) for c in range(z+1) if a+b+c!=n ]