finish day 2
This commit is contained in:
224
day2.cpp
224
day2.cpp
@@ -10,143 +10,181 @@
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#include "doctest.h"
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#include "doctest.h"
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namespace day2 {
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namespace day2 {
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const std::string sample =
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const std::string sample =
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"11-22,95-115,998-1012,1188511880-1188511890,222220-222224,1698522-1698528,"
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"11-22,95-115,998-1012,1188511880-1188511890,222220-222224,1698522-1698528,"
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"446443-446449,38593856-38593862,565653-565659,824824821-824824827,"
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"446443-446449,38593856-38593862,565653-565659,824824821-824824827,"
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"2121212118-2121212124";
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"2121212118-2121212124";
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struct Range {
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struct Range {
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uint64_t start;
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uint64_t start;
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uint64_t end;
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uint64_t end;
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};
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};
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} // namespace day2
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} // namespace day2
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template<>
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template<>
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struct std::formatter<day2::Range> : std::formatter<std::string_view> {
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struct std::formatter<day2::Range> : std::formatter<std::string_view> {
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static auto format(const day2::Range &i, std::format_context &ctx) {
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static auto format(const day2::Range &i, std::format_context &ctx) {
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return std::format_to(ctx.out(), "Range[start: {}, end: {}]", i.start,i.end);
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return std::format_to(ctx.out(), "Range[start: {}, end: {}]", i.start, i.end);
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}
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}
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};
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};
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namespace day2 {
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namespace day2 {
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Range parse_range(std::string_view s) {
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Range parse_range(std::string_view s) {
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std::string_view start;
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std::string_view start;
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std::string_view end;
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std::string_view end;
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for (size_t i = 0; i < s.size(); i++) {
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for (size_t i = 0; i < s.size(); i++) {
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const char c = s[i];
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const char c = s[i];
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if (c == '-') {
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if (c == '-') {
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start = {s.data(), i};
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start = {s.data(), i};
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end = {s.data() + i + 1, s.size() - start.size()};
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end = {s.data() + i + 1, s.size() - start.size()};
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}
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}
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}
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}
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Range range;
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Range range{};
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uint64_t parsed;
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uint64_t parsed;
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std::from_chars(start.data(), start.end(), parsed);
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std::from_chars(start.data(), start.end(), parsed);
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range.start = parsed;
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range.start = parsed;
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std::from_chars(end.data(), end.end(), parsed);
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std::from_chars(end.data(), end.end(), parsed);
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range.end = parsed;
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range.end = parsed;
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return range;
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return range;
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}
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}
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size_t find_divisor(uint64_t n) {
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size_t find_divisor(const uint64_t n) {
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for (size_t i = 1;; i++) {
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for (size_t i = 1;; i++) {
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size_t div = n / std::pow(10, i);
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size_t div = n / std::pow(10, i);
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if (div == 0) {
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if (div == 0) {
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return std::pow(10, (i / 2));
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return std::pow(10, i / 2);
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}
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}
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}
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}
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assert(0 && "Unreachable");
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assert(0 && "Unreachable");
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}
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}
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uint64_t count_repetitions(const Range range) {
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uint64_t count_repetitions(const Range range) {
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uint64_t total = 0;
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uint64_t total = 0;
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for (uint64_t n = range.start; n <= range.end; n++) {
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for (uint64_t n = range.start; n <= range.end; n++) {
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auto div = find_divisor(n);
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auto div = find_divisor(n);
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auto left = n / div;
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auto left = n / div;
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auto right = n % div;
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auto right = n % div;
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if (left == right) total++;
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if (left == right) total++;
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}
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}
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return total;
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return total;
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}
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}
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uint64_t sum_repetitions(const Range range) {
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uint64_t sum_repetitions(const Range range) {
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uint64_t total = 0;
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uint64_t total = 0;
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for (uint64_t n = range.start; n <= range.end; n++) {
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for (uint64_t n = range.start; n <= range.end; n++) {
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auto div = find_divisor(n);
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const auto div = find_divisor(n);
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auto left = n / div;
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const auto left = n / div;
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auto right = n % div;
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const auto right = n % div;
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if (left == right) total += n;
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if (left == right) total += n;
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}
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}
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return total;
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return total;
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}
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}
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uint64_t solve_first(std::string_view input) {
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uint64_t solve_first(std::string_view input) {
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uint64_t result = 0;
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uint64_t result = 0;
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for (const auto range :
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for (const auto range:
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std::views::split(input, ',') | std::views::transform([](auto s) {
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std::views::split(input, ',') | std::views::transform([](auto s) {
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return parse_range(std::string_view(s));
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return parse_range(std::string_view(s));
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})) {
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})) {
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result += sum_repetitions(range);
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result += sum_repetitions(range);
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}
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}
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return result;
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return result;
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}
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}
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uint64_t sum_repetitions_2(const Range range, std::string& buf) {
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uint64_t sum_repetitions_2(const Range range, std::string &buf) {
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uint64_t total = 0;
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uint64_t total = 0;
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for (uint64_t n = range.start; n <= range.end; n++) {
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for (uint64_t n = range.start; n <= range.end; n++) {
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std::format_to(buf, "{}", n);
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std::format_to(std::back_inserter(buf), "{}", n);
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size_t size = buf.size();
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for (int i = 0; i < size; ++i) {
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if (size % i != 0 || size / i == 1) continue;
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std::string_view first_partition(buf.data(), i);
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bool all_equal = true;
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for (int j = i; j < size; j += i) {
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std::string_view partition(buf.data() + j, i);
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if (partition != first_partition) {
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all_equal = false;
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break;
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}
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}
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if (all_equal) {
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total += n;
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break;
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}
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}
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buf.clear();
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}
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}
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return total;
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return total;
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}
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}
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uint64_t solve_second(std::string_view input) {
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uint64_t solve_second(std::string_view input) {
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std::string buf;
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std::string buf;
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buf.reserve(100);
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buf.reserve(100);
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uint64_t result = 0;
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uint64_t result = 0;
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for (const auto range :
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for (const auto range:
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std::views::split(input, ',') | std::views::transform([](auto s) {
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std::views::split(input, ',') | std::views::transform([](auto s) {
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return parse_range(std::string_view(s));
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return parse_range(std::string_view(s));
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})) {
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})) {
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result += sum_repetitions_2(range, buf);
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result += sum_repetitions_2(range, buf);
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buf.clear();
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buf.clear();
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}
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}
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return result;
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return result;
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}
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}
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TEST_CASE("Can parse input") {
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TEST_CASE("Can parse input") {
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auto range = parse_range("11-22");
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auto range = parse_range("11-22");
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CHECK(range.start == 11);
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CHECK(range.start == 11);
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CHECK(range.end == 22);
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CHECK(range.end == 22);
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}
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}
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TEST_CASE("Solve first sample") {
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TEST_CASE("Solve first sample") {
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CHECK(solve_first(sample) == 1227775554);
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CHECK(solve_first(sample) == 1227775554);
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}
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}
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TEST_CASE("Solve first input") {
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TEST_CASE("Solve first input") {
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std::ifstream fs("day2input.txt");
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std::ifstream fs("day2input.txt");
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std::stringstream ss{};
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std::stringstream ss{};
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ss << fs.rdbuf();
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ss << fs.rdbuf();
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CHECK(solve_first(ss.str()) == 1227775554);
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CHECK(solve_first(ss.str()) == 21898734247);
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}
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}
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TEST_CASE("Find divisor works") {
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TEST_CASE("Find divisor works") {
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CHECK(find_divisor(11) == 10);
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CHECK(find_divisor(11) == 10);
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CHECK(find_divisor(1221) == 100);
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CHECK(find_divisor(1221) == 100);
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CHECK(find_divisor(222222) == 1000);
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CHECK(find_divisor(222222) == 1000);
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}
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}
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TEST_CASE("Count repetition works") {
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TEST_CASE("Count repetition works") {
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CHECK(count_repetitions({.start = 11, .end = 22}) == 2);
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CHECK(count_repetitions({.start = 11, .end = 22}) == 2);
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CHECK(count_repetitions({.start = 1188511880, .end = 1188511890}) == 1);
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CHECK(count_repetitions({.start = 1188511880, .end = 1188511890}) == 1);
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}
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}
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TEST_CASE("sum_repetitions_2") {
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std::string buf;
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buf.reserve(100);
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CHECK(sum_repetitions_2({95, 115}, buf) == 210);
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buf.clear();
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CHECK(sum_repetitions_2({998, 1012}, buf) == 999 + 1010);
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}
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TEST_CASE("Solves second sample") {
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CHECK(solve_second(sample) == 4174379265);
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}
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TEST_CASE("Solves second input") {
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std::ifstream fs("day2input.txt");
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std::stringstream ss{};
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ss << fs.rdbuf();
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CHECK(solve_second(ss.view()) == 28915664389);
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}
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} // namespace day2
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} // namespace day2
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