167 lines
3.4 KiB
C++
167 lines
3.4 KiB
C++
#include <BAN/HashMap.h>
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#include <BAN/String.h>
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#include <BAN/Swap.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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u64 parse_u64(BAN::StringView str)
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{
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u64 result = 0;
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for (char c : str)
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if (isdigit(c))
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result = (result * 10) + (c - '0');
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return result;
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}
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static BAN::HashMap<BAN::String, i64> s_cache;
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BAN::String build_cache_key(BAN::StringView record, BAN::Span<u64> groups)
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{
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BAN::String cache_key;
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MUST(cache_key.append(record));
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for (u64 group : groups)
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MUST(cache_key.append(BAN::String::formatted(" {}", group)));
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return cache_key;
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}
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i64 count_possibilities(BAN::StringView record, BAN::Span<u64> groups)
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{
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if (groups.empty())
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return !record.contains('#');
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if (record.empty())
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return 0;
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auto cache_key = build_cache_key(record, groups);
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if (s_cache.contains(cache_key))
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return s_cache[cache_key];
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i64 result = 0;
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for (size_t i = 0; i + groups[0] <= record.size(); i++)
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{
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bool valid = true;
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if (record.substring(i, groups[0]).contains('.'))
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valid = false;
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if (i + groups[0] < record.size() && record[i + groups[0]] == '#')
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valid = false;
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if (valid)
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{
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auto next_record = record.substring(i + groups[0]);
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if (!next_record.empty())
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next_record = next_record.substring(1);
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result += count_possibilities(next_record, groups.slice(1));
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}
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if (record[i] == '#')
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break;
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}
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//printf("inserting... "); fflush(stdout);
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MUST(s_cache.insert(cache_key, result));
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//printf("done\n");
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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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i64 result = 0;
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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 line(buffer);
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if (line.back() == '\n')
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line = line.substring(0, line.size() - 1);
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if (line.size() < 3)
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continue;
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auto parts = MUST(line.split(' '));
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auto record = parts[0];
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auto continuous_strs = MUST(parts[1].split(','));
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BAN::Vector<u64> continuous(continuous_strs.size());
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for (size_t i = 0; i < continuous.size(); i++)
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continuous[i] = parse_u64(continuous_strs[i]);
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result += count_possibilities(record, continuous.span());
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}
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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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i64 result = 0;
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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 line(buffer);
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if (line.back() == '\n')
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line = line.substring(0, line.size() - 1);
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if (line.size() < 3)
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continue;
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auto parts = MUST(line.split(' '));
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BAN::String record;
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MUST(record.reserve(parts[0].size() + 4));
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for (size_t i = 0; i < 5; i++)
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{
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if (i > 0)
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MUST(record.push_back('?'));
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MUST(record.append(parts[0]));
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}
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auto continuous_strs = MUST(parts[1].split(','));
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BAN::Vector<u64> continuous(5 * continuous_strs.size());
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for (size_t i = 0; i < continuous.size(); i++)
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continuous[i] = parse_u64(continuous_strs[i % continuous_strs.size()]);
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result += count_possibilities(record, continuous.span());
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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/day12_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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