[Daily Challenge #115 - Intermediate] - Sum-Pairings - r/DailyProgrammer

Challenge_115_intermediate.py

# ***** DAILY CHALLENGE #115 - INTERMEDIATE *****

# (Intermediate): Sum-Parings
#
# Let the term "sum-pair" be a pair of integers A and B such that the sum of
# A and B equals a given number C. As an example, let C be 10. Thus,
# the pairs (5, 5), (1, 9), (2, 8), etc. are all sum-pairs of 10.
#
# Your goal is to write a program that, given an array through standard
# input (console), you echo out all sum-pairs of a given integer C.
#
# Formal Inputs & Outputs
#
# Input Description:
#
# On the console, you will be first given an integer N. This is the number
# of following integers that are part of the array. After the N integers,
# you will be given an integer C which represents the sum-pair you are
# attempting to match.
#
# Output Description
#
# Your program must print all unique pair of integers in the given list,
# where the sum of the pair is equal to integer C.
#
# Sample Inputs & Outputs
#
# Input (Through Console)
#
# 4
# 1 -3 4 10aw
# 5
#
# Output (Through Console)
#
# 1, 4
#
# Note that there is only one pair printed to the console since there is
# only one unique pair (1, 4) that has the sum of C (5).
#
# Challenge Input
#
# We will show the solution of this problem data-set in 7-days after the
# original submission.
#
# 14
# 10 -8 2 1 4 -9 6 1 9 -10 -5 2 3 7
# 7
#
# Note
#
# (Awesome points awarded to /u/drigz for getting some important information
# into my thick-skull: there are linear-time solutions!)
#
# This is a common interviewing problem for programming jobs, so treat it as
# such! There is a very trivial solution, but the trivial solution will run
# in O(N2 ) time. There are a few other known solutions: one that runs in
# O(N Log(N)) time (hint: takes advantage of sorting), and another in linear
# time (hint: dictionary).

# -----------------------------------------------------------------------------


def sum_pairings(numbers, n, c):
    """Get unique pairings for sum-pairing i + j in numbers.

    Args:
        numbers (list): Numbers to add.
        n (int): Number of numbers to add.
        c (int): Number to add to.

    Returns:
        list: Contains all unique pairings of summing i + j.
    """
    pairings = []
    numbers = numbers[:n+1]
    for i in numbers:
        for j in numbers:
            if i + j == c and (j, i) not in pairings:
                pairings.append((i, j))
    pairings.sort()
    return pairings


def main():
    """Print pair in pairings from sum_pairings(numbers, n, c)."""
    numbers = [1, -3, 4, 10]
    n, c = 4, 5
    pairings = sum_pairings(numbers, n, c)

    for pair in pairings:
        print(pair)

if __name__ == "__main__":
    main()

[Daily Challenge #115 - Intermediate] from the DailyProgrammer subreddit. Sum-Pairings.

Reference: https://www.reddit.com/r/dailyprogrammer/comments/15wm48/132013_challenge_115_intermediate_sumpairings/