forked from Bananymous/banan-os
151 lines
2.7 KiB
C++
151 lines
2.7 KiB
C++
#include <BAN/Array.h>
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#include <BAN/LinkedList.h>
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#include <BAN/String.h>
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#include <BAN/StringView.h>
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#include <BAN/Vector.h>
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#include <ctype.h>
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#include <inttypes.h>
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#include <stdio.h>
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using i8 = int8_t;
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using i16 = int16_t;
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using i32 = int32_t;
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using i64 = int64_t;
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using u8 = uint8_t;
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using u16 = uint16_t;
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using u32 = uint32_t;
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using u64 = uint64_t;
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i64 parse_i64(BAN::StringView string)
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{
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i64 result = 0;
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for (char c : string)
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result = (result * 10) + (c - '0');
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return result;
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}
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BAN::Vector<BAN::StringView> parse_instructions(FILE* fp)
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{
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static BAN::String line;
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char buffer[128];
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while (fgets(buffer, sizeof(buffer), fp))
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{
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BAN::StringView buffer_sv(buffer);
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MUST(line.append(buffer_sv));
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if (buffer_sv.back() == '\n')
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{
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line.pop_back();
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break;
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}
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}
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return MUST(line.sv().split(','));
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}
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i64 calculate_hash(BAN::StringView string)
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{
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i64 result = 0;
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for (char c : string)
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result = ((result + c) * 17) % 256;
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return result;
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}
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i64 puzzle1(FILE* fp)
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{
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auto instructions = parse_instructions(fp);
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i64 result = 0;
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for (auto insn : instructions)
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result += calculate_hash(insn);
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return result;
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}
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i64 puzzle2(FILE* fp)
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{
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struct Entry
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{
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BAN::String label;
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i64 focal_length;
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};
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using Box = BAN::LinkedList<Entry>;
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auto instructions = parse_instructions(fp);
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BAN::Array<Box, 256> boxes;
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for (auto insn : instructions)
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{
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if (insn.back() == '-')
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{
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auto label = insn.substring(0, insn.size() - 1);
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i64 hash = calculate_hash(label);
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for (auto it = boxes[hash].begin(); it != boxes[hash].end(); it++)
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{
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if (it->label == label)
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{
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boxes[hash].remove(it);
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break;
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}
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}
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}
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else
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{
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auto temp = MUST(insn.split('='));
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auto label = temp[0];
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auto focal_length = parse_i64(temp[1]);
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i64 hash = calculate_hash(label);
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bool found = false;
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for (auto it = boxes[hash].begin(); it != boxes[hash].end(); it++)
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{
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if (it->label == label)
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{
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it->focal_length = focal_length;
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found = true;
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break;
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}
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}
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if (!found)
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MUST(boxes[hash].emplace_back(label, focal_length));
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}
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}
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i64 result = 0;
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for (size_t i = 0; i < boxes.size(); i++)
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{
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size_t slot = 0;
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for (auto it = boxes[i].begin(); it != boxes[i].end(); it++, slot++)
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result += (i + 1) * (slot + 1) * it->focal_length;
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}
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return result;
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}
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int main(int argc, char** argv)
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{
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const char* file_path = "/usr/share/aoc2023/day15_input.txt";
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if (argc >= 2)
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file_path = argv[1];
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FILE* fp = fopen(file_path, "r");
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if (fp == nullptr)
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{
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perror("fopen");
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return 1;
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}
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printf("puzzle1: %" PRId64 "\n", puzzle1(fp));
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fseek(fp, 0, SEEK_SET);
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printf("puzzle2: %" PRId64 "\n", puzzle2(fp));
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fclose(fp);
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}
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