From 0c3e5980d68bfca520338639f0c3392f9eac2cf8 Mon Sep 17 00:00:00 2001 From: Bananymous Date: Sat, 9 Dec 2023 16:22:43 +0200 Subject: [PATCH] AOC2023: Implement day9 --- userspace/aoc2023/CMakeLists.txt | 1 + userspace/aoc2023/day9/CMakeLists.txt | 22 ++++ userspace/aoc2023/day9/main.cpp | 148 ++++++++++++++++++++++++++ 3 files changed, 171 insertions(+) create mode 100644 userspace/aoc2023/day9/CMakeLists.txt create mode 100644 userspace/aoc2023/day9/main.cpp diff --git a/userspace/aoc2023/CMakeLists.txt b/userspace/aoc2023/CMakeLists.txt index e528db32..e1a7b83d 100644 --- a/userspace/aoc2023/CMakeLists.txt +++ b/userspace/aoc2023/CMakeLists.txt @@ -11,6 +11,7 @@ set(AOC2023_PROJECTS day6 day7 day8 + day9 ) set(BANAN_AOC2023_BIN ${BANAN_BIN}/aoc2023) diff --git a/userspace/aoc2023/day9/CMakeLists.txt b/userspace/aoc2023/day9/CMakeLists.txt new file mode 100644 index 00000000..4f630f8c --- /dev/null +++ b/userspace/aoc2023/day9/CMakeLists.txt @@ -0,0 +1,22 @@ +cmake_minimum_required(VERSION 3.26) + +project(aoc2023_day9 CXX) + +set(SOURCES + main.cpp +) + +add_executable(aoc2023_day9 ${SOURCES}) +target_compile_options(aoc2023_day9 PUBLIC -O2 -g) +target_link_libraries(aoc2023_day9 PUBLIC libc ban) + +add_dependencies(aoc2023_day9 libc-install ban-install) + +add_custom_target(aoc2023_day9-install + COMMAND ${CMAKE_COMMAND} -E copy ${CMAKE_CURRENT_BINARY_DIR}/aoc2023_day9 ${BANAN_AOC2023_BIN}/day9 + DEPENDS aoc2023_day9 + DEPENDS aoc2023_always +) + +add_dependencies(aoc2023 aoc2023_day9) +add_dependencies(aoc2023-install aoc2023_day9-install) diff --git a/userspace/aoc2023/day9/main.cpp b/userspace/aoc2023/day9/main.cpp new file mode 100644 index 00000000..df2d31b3 --- /dev/null +++ b/userspace/aoc2023/day9/main.cpp @@ -0,0 +1,148 @@ +#include +#include + +#include +#include +#include + +using i32 = int32_t; +using i64 = int64_t; + +using u32 = uint32_t; +using u64 = uint64_t; + +i64 parse_i64(BAN::StringView sv) +{ + bool negative = (!sv.empty() && sv.front() == '-'); + if (negative) + sv = sv.substring(1); + + i64 result = 0; + for (char c : sv) + { + if (!isdigit(c)) + break; + result = (result * 10) + (c - '0'); + } + return negative ? -result : result; +} + +i64 puzzle1(FILE* fp) +{ + i64 result = 0; + + char buffer[128]; + while (fgets(buffer, sizeof(buffer), fp)) + { + BAN::StringView line(buffer); + + auto value_strs = MUST(line.split(' ')); + if (value_strs.empty()) + continue; + + BAN::Vector> values; + MUST(values.emplace_back(value_strs.size() + 1, 0)); + for (size_t i = 0; i < value_strs.size(); i++) + values.back()[i] = parse_i64(value_strs[i]); + + bool all_zeroes = false; + while (!all_zeroes) + { + size_t last = values.size(); + MUST(values.emplace_back(values.back().size() - 1, 0)); + + all_zeroes = true; + for (size_t i = 0; i < values.back().size() - 1; i++) + { + i64 lhs = values[last - 1][i + 0]; + i64 rhs = values[last - 1][i + 1]; + values[last][i] = rhs - lhs; + if (values[last][i] != 0) + all_zeroes = false; + } + } + + for (size_t i = values.size() - 1; i > 0; i--) + { + const size_t len = values[i].size(); + i64 lhs = values[i - 1][len - 1]; + i64 res = values[i][len - 1]; + values[i - 1][len - 0] = res + lhs; + } + + result += values.front().back(); + } + + return result; +} + +i64 puzzle2(FILE* fp) +{ + i64 result = 0; + + char buffer[128]; + while (fgets(buffer, sizeof(buffer), fp)) + { + BAN::StringView line(buffer); + + auto value_strs = MUST(line.split(' ')); + if (value_strs.empty()) + continue; + + BAN::Vector> values; + MUST(values.emplace_back(value_strs.size() + 1, 0)); + for (size_t i = 0; i < value_strs.size(); i++) + values.back()[i + 1] = parse_i64(value_strs[i]); + + bool all_zeroes = false; + while (!all_zeroes) + { + size_t last = values.size(); + MUST(values.emplace_back(values.back().size() - 1, 0)); + + all_zeroes = true; + for (size_t i = 1; i < values.back().size(); i++) + { + i64 lhs = values[last - 1][i + 0]; + i64 rhs = values[last - 1][i + 1]; + values[last][i] = rhs - lhs; + if (values[last][i] != 0) + all_zeroes = false; + } + } + + for (size_t i = values.size() - 1; i > 0; i--) + { + i64 rhs = values[i - 1][1]; + i64 res = values[i][0]; + values[i - 1][0] = rhs - res; + } + + result += values.front().front(); + } + + return result; +} + +int main(int argc, char** argv) +{ + const char* file_path = "/usr/share/aoc2023/day9_input.txt"; + + if (argc >= 2) + file_path = argv[1]; + + FILE* fp = fopen(file_path, "r"); + if (fp == nullptr) + { + perror("fopen"); + return 1; + } + + printf("puzzle1: %lld\n", puzzle1(fp)); + + fseek(fp, 0, SEEK_SET); + + printf("puzzle2: %lld\n", puzzle2(fp)); + + fclose(fp); +}