Find newest note of every number occur and also remove duplicate number.

summarize_notes.py

import itertools


def summarize_notes(case):
    found = set()
    for note, numbers in case:
        snumbers = set(numbers)
        output = list(snumbers - found)
        found |= snumbers
        if output:
            yield [note, output]


def summarize_notes2(case):
    found = set(range(5))
    for note, numbers in case:
        output = list(itertools.takewhile(lambda x: x in found, numbers))
        found -= set(output)
        if output:
            yield [note, output]


def summarize_notes3(case):
    found = set(range(5))
    for note, numbers in case:
        snumbers = set(numbers)
        output = list(snumbers & found)
        found -= set(output)
        if output:
            yield [note, output]


cases = [
    [
        [["Note2", [1, 2, 3]], ["Note1", []]],
        [["Note2", [1, 2, 3]]]
    ],
    [
        [["Note2", [1]], ["Note1", [0, 1]]],
        [["Note2", [1]], ["Note1", [0]]]
    ],
    [
        [["Note2", [0, 1]], ["Note1", [0]]],
        [["Note2", [0, 1]]]
    ],
    [
        [["Note2", [1, 2, 3]], ["Note1", [0, 1, 2]]],
        [["Note2", [1, 2, 3]], ["Note1", [0]]]
    ],
    [
        [["Note5", [1, 2]], ["Note4", [4]], ["Note3", [0, 2]], ["Note2", [2]], ["Note1", [0]]],
        [["Note5", [1, 2]], ["Note4", [4]], ["Note3", [0]]]
    ]
]


for case, answer in cases:
    assert list(summarize_notes(case)) == answer
    assert list(summarize_notes2(case)) == answer
    assert list(summarize_notes3(case)) == answer