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Streamline 2024 day 5 part 1

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SebastianStork 2024-12-18 22:13:14 +01:00
parent 078ccb78ef
commit ca9f0d37ae
1 changed files with 34 additions and 63 deletions
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97
2024/day-05/main.cpp
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@ -15,7 +15,7 @@ vector<pair<int, int>> readRules()
} }
int number1 = stoi(line.substr(0, 2)); int number1 = stoi(line.substr(0, 2));
int number2 = stoi(line.substr(3, 2)); int number2 = stoi(line.substr(3, 2));
rules.push_back(make_pair(number1, number2)); rules.push_back({number1, number2});
} }
return rules; return rules;
} }
@ -25,71 +25,51 @@ vector<vector<int>> readManuals()
vector<vector<int>> manuals; vector<vector<int>> manuals;
string line; string line;
while (getline(cin, line)) { while (getline(cin, line)) {
manuals.push_back({});
stringstream inStream(line); stringstream inStream(line);
vector<int> pages;
string page; string page;
while (getline(inStream, page, ',')) { while (getline(inStream, page, ',')) {
manuals.back().push_back(stoi(page)); pages.push_back(stoi(page));
} }
manuals.push_back(pages);
} }
return manuals; return manuals;
} }
vector<pair<int, int>> getSortedLessThanRules(vector<pair<int, int>> rules) void sortRules(vector<pair<int, int>> &rules)
{ {
sort(rules.begin(), rules.end(), [](auto a, auto b) { return a.first < b.first; }); sort(rules.begin(), rules.end(), [](const pair<int, int> &a, const pair<int, int> &b) {
return rules; return a.first < b.first;
});
} }
vector<pair<int, int>> getSortedGreaterThanRules(vector<pair<int, int>> rules) bool isCorrectPageOrdering(const int firstPage,
const int secondPage,
const vector<pair<int, int>> &rules)
{ {
for (pair<int, int> &rule : rules) { auto it = lower_bound(rules.begin(),
swap(rule.first, rule.second); rules.end(),
} secondPage,
sort(rules.begin(), rules.end(), [](auto a, auto b) { return a.first < b.first; }); [](const pair<int, int> &a, int b) { return a.first < b; });
return rules;
}
enum class Comparison { lessThan, greaterThan }; for (; it != rules.end() && it->first == secondPage; ++it) {
if (it->second == firstPage) {
bool pageIsFollowingRules(const vector<int> &pages, return false;
const size_t indexOfPageToCheck,
const vector<pair<int, int>> &rules,
const Comparison ruleType)
{
size_t indexOfFirstRule = lower_bound(rules.begin(),
rules.end(),
pages[indexOfPageToCheck],
[](pair<int, int> a, int b) { return a.first < b; })
- rules.begin();
if (indexOfFirstRule == rules.size()) {
return true;
}
size_t pagesStart, pagesEnd;
if (ruleType == Comparison::lessThan) {
pagesStart = 0;
pagesEnd = indexOfPageToCheck;
} else {
pagesStart = indexOfPageToCheck;
pagesEnd = pages.size();
}
for (size_t pageIndex = pagesStart; pageIndex < pagesEnd; pageIndex++) {
for (size_t ruleIndex = indexOfFirstRule;
ruleIndex < rules.size() && rules[ruleIndex].first == pages[indexOfPageToCheck];
ruleIndex++) {
if (pages[pageIndex] == rules[ruleIndex].second) {
return false;
}
} }
} }
return true; return true;
} }
int getMiddlePageNumber(vector<int> pages) vector<int> getProperlyOrderedPages(vector<int> pages, const vector<pair<int, int>> &rules)
{
sort(pages.begin(), pages.end(), [&rules](int a, int b) {
return isCorrectPageOrdering(a, b, rules);
});
return pages;
}
int getMiddlePageNumber(const vector<int> &pages)
{ {
size_t middleIndex = pages.size() / 2; size_t middleIndex = pages.size() / 2;
return pages[middleIndex]; return pages[middleIndex];
@ -97,29 +77,20 @@ int getMiddlePageNumber(vector<int> pages)
int main() int main()
{ {
vector<pair<int, int>> unsortedRules = readRules(); vector<pair<int, int>> rules = readRules();
vector<vector<int>> manuals = readManuals(); vector<vector<int>> manuals = readManuals();
sort(rules.begin(), rules.end());
vector<pair<int, int>> lessThanRules = getSortedLessThanRules(unsortedRules); int sumOfCorrectMiddlePages = 0;
vector<pair<int, int>> greaterThanRules = getSortedGreaterThanRules(unsortedRules);
int middlePageNumberSum = 0;
for (const vector<int> &pages : manuals) { for (const vector<int> &pages : manuals) {
bool correctlyOrdered = true; const vector<int> properlyOrderedPages = getProperlyOrderedPages(pages, rules);
for (size_t i = 0; i < pages.size(); i++) { if (pages == properlyOrderedPages) {
if (!pageIsFollowingRules(pages, i, lessThanRules, Comparison::lessThan) sumOfCorrectMiddlePages += getMiddlePageNumber(pages);
|| !pageIsFollowingRules(pages, i, greaterThanRules, Comparison::greaterThan)) {
correctlyOrdered = false;
break;
}
}
if (correctlyOrdered) {
middlePageNumberSum += getMiddlePageNumber(pages);
} }
} }
// Part one // Part one
cout << "Sum of the middle page numbers of all correctly ordered manuals: " cout << "Sum of the middle page numbers of all correctly ordered manuals: "
<< middlePageNumberSum << endl; << sumOfCorrectMiddlePages << endl;
} }