Advent of Code: Day 5
Day5: Print Queue
Check out Print Queue for the day5 puzzle.
Part 1
Day 4 took me a while, so I was relived to find that day 5 was a faster for me to solve.
Part 1 Solution:
testPath = './testInput.txt'
inputPath = './input.txt'
chosenPath = inputPath
def parseInput(path):
pageOrderingRules = []
updates = []
file = open(path, 'r')
for line in file:
if '|' in line:
line = line.strip('
').split('|')
line = list(map(int, line))
pageOrderingRules.append(line)
elif ',' in line:
line = line.strip('
').split(',')
line = list(map(int, line))
updates.append(line)
return pageOrderingRules, updates
pageOrderingRules, updates = parseInput(chosenPath)
def getValidUpdates(rules, updates):
invalidUpdates = []
updatesCopy = updates.copy()
def getPrecedingPages(page, rules):
precedingPages = []
for before, after in rules:
if after == page:
precedingPages.append(before)
return precedingPages
def getFollowingPages(page, rules):
followingPages = []
for before, after in rules:
if before == page:
followingPages.append(after)
return followingPages
for update in updates:
for pageSeq, page in enumerate(update):
precedingPages = getPrecedingPages(page, rules)
followingPages = getFollowingPages(page, rules)
for precedingPage in precedingPages:
if precedingPage in update[pageSeq:] and update.index(precedingPage) > pageSeq:
invalidUpdates.append(update)
break
for followingPage in followingPages:
if followingPage in update[:pageSeq] and update.index(followingPage) < pageSeq:
if update not in invalidUpdates:
invalidUpdates.append(update)
break
for invalidUpdate in invalidUpdates:
if invalidUpdate in updatesCopy:
updatesCopy.remove(invalidUpdate)
return updatesCopy
validUpdates = getValidUpdates(pageOrderingRules, updates)
def getMidPoint(arrays):
midPoints = []
for array in arrays:
midPointIndex = len(array) // 2
midPoints.append(array[midPointIndex])
return midPoints
midPoints = getMidPoint(validUpdates)
print(sum(midPoints))Part 2
This took me a while.
I understood what had to be done, but every time I reordered any pages that needed more than 1 set of pages to be swapped around, I got a got a bad answer. After a few tries and some logging, i found that I was swapping the same pages over and over again. I modified the swap function to get the index of the pages to be swapped and then this came together.
Part 2 Solution:
testPath = './testInput.txt'
inputPath = './input.txt'
chosenPath = inputPath
def parseInput(path):
pageOrderingRules = []
updates = []
file = open(path, 'r')
for line in file:
if '|' in line:
line = line.strip('
').split('|')
line = list(map(int, line))
pageOrderingRules.append(line)
elif ',' in line:
line = line.strip('
').split(',')
line = list(map(int, line))
updates.append(line)
return pageOrderingRules, updates
pageOrderingRules, updates = parseInput(chosenPath)
def getInvalidUpdates(rules, updates):
invalidUpdates = []
def getPrecedingPages(page, rules):
precedingPages = []
for before, after in rules:
if after == page:
precedingPages.append(before)
return precedingPages
def getFollowingPages(page, rules):
followingPages = []
for before, after in rules:
if before == page:
followingPages.append(after)
return followingPages
for update in updates:
for pageSeq, page in enumerate(update):
precedingPages = getPrecedingPages(page, rules)
followingPages = getFollowingPages(page, rules)
for precedingPage in precedingPages:
if precedingPage in update[pageSeq:] and update.index(precedingPage) > pageSeq:
if update not in invalidUpdates:
invalidUpdates.append(update)
break
for followingPage in followingPages:
if followingPage in update[:pageSeq] and update.index(followingPage) < pageSeq:
if update not in invalidUpdates:
invalidUpdates.append(update)
break
return invalidUpdates
invalidUpdates = getInvalidUpdates(pageOrderingRules, updates)
def sortUpdates(rules, update):
results = []
def getApplicableRules(update, rules):
matchedRules = []
applicableRules = []
for rule in rules:
if rule[0] in update and rule[1] in update:
matchedRules.append(rule)
for rule in matchedRules:
if update.index(rule[0]) > update.index(rule[1]):
applicableRules.append(rule)
return applicableRules
def swapPages(page1, page2, update):
page1Index = update.index(page1)
page2Index = update.index(page2)
update[page1Index], update[page2Index] = update[page2Index], update[page1Index]
return update
def reorder(update, rules):
applicableRules = getApplicableRules(update, rules)
if len(applicableRules) > 0:
for rule in applicableRules:
update = swapPages(rule[0], rule[1], update)
return reorder(update, rules)
return update
reorderedUpdate = reorder(update, rules)
rules = getApplicableRules(reorderedUpdate, rules)
if len(rules) <= 0:
results.append(reorderedUpdate)
return results
results = []
for update in invalidUpdates:
sortedUpdates = sortUpdates(pageOrderingRules, update)
results.extend(sortedUpdates)
def getMidPoint(arrays):
print(f'arrays: {arrays}')
midPoints = []
for array in arrays:
print(f'looking at array: {array}')
midPointIndex = len(array) // 2
print(f' the midpoing is page: {array[midPointIndex]}')
midPoints.append(array[midPointIndex])
return midPoints
midponts = getMidPoint(results)
print(f' sum of midpoints is: {sum(midponts)}')