readme.md

Given an array of positive integers, write a function which returns all the unique pairs which add (equal) up to 100.

Example data:

sample_data = [0, 1, 100, 99, 0, 10, 90, 30, 55, 33, 55, 75, 50, 51, 49, 50, 51, 49, 51]
sample_output = [[1,99], [0,100], [10,90], [51,49], [50,50]]

solution.py

def f(lst):
    xs = sorted(lst)
    ps = []
    i = 0
    j = len(lst) - 1
    while i < j:
        if xs[i] + xs[j] == 100:
            ps.append((xs[i], xs[j]))
            i += 1
            j -= 1
        elif xs[i] + xs[j] > 100:
            j -= 1
        elif xs[i] + xs[j] < 100:
            i += 1
    return set(ps)