69 lines
1.8 KiB
C++
69 lines
1.8 KiB
C++
//
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// Created by Grant Horner on 12/3/25.
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//
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#include <ranges>
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#include <string>
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#include "doctest.h"
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#include "utils.h"
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namespace day3 {
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const std::string sample = "987654321111111\n"
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"811111111111119\n"
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"234234234234278\n"
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"818181911112111\n";
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auto split_into_banks(const std::string_view input) {
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return std::views::split(input, '\n')
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| std::views::transform(utils::to_string_view)
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| std::views::filter(utils::non_empty);
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}
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uint64_t solve(const std::string_view input, uint8_t num_batteries) {
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uint64_t sum = 0;
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for (auto split: split_into_banks(input)) {
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uint64_t bank = 0;
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size_t largest_index = 0;
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for (size_t i = num_batteries; i > 0; i--) {
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const auto num_reserved = i - 1;
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const auto substr_len = split.size() - largest_index - num_reserved;
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const auto not_last = split.substr(largest_index, substr_len);
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size_t temp_largest_index = 0;
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uint8_t largest = 0;
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for (size_t j = 0; j < not_last.size(); j++) {
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if (const char c = not_last[j]; c > largest) {
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largest = c;
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temp_largest_index = 1 + j;
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}
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}
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largest_index += temp_largest_index;
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bank += (largest - '0') * std::pow(10, i - 1);
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}
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sum += bank;
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}
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return sum;
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}
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TEST_SUITE_BEGIN("Day 3");
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TEST_CASE("solve first sample") {
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CHECK(solve(sample, 2) == 357);
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}
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TEST_CASE("solve first puzzle") {
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CHECK(solve(utils::read_file("day3input.txt"),2) == 17095);
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}
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TEST_CASE("solve second sample") {
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CHECK(solve(sample, 12) == 3121910778619);
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}
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TEST_CASE("solve second input") {
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CHECK(solve(utils::read_file("day3input.txt"), 12) == 168794698570517);
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}
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TEST_SUITE_END();
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}
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