forked from Bananymous/banan-os
118 lines
2.3 KiB
C++
118 lines
2.3 KiB
C++
#include <BAN/HashMap.h>
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#include <BAN/HashSet.h>
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#include <BAN/Vector.h>
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#include <inttypes.h>
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#include <stdio.h>
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#include <stdlib.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 isize = ssize_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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using usize = size_t;
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static constexpr u64 generate_next_secret(u64 secret)
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{
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secret = (secret ^ (secret << 6)) & 0xFFFFFF;
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secret = (secret ^ (secret >> 5)) & 0xFFFFFF;
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secret = (secret ^ (secret << 11)) & 0xFFFFFF;
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return secret;
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}
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i64 part1(FILE* fp)
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{
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u64 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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u64 secret = atoll(buffer);
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for (usize i = 0; i < 2000; i++)
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secret = generate_next_secret(secret);
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result += secret;
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}
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return result;
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}
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i64 part2(FILE* fp)
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{
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union Sequence
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{
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u32 raw;
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i8 diffs[4];
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};
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BAN::HashMap<u32, u64> sequence_to_bananas;
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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::Vector<u8> values;
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MUST(values.reserve(2001));
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u64 secret = atoll(buffer);
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MUST(values.push_back(secret % 10));
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for (usize i = 0; i < 2000; i++)
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{
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secret = generate_next_secret(secret);
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MUST(values.push_back(secret % 10));
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}
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BAN::HashSet<u32> found_sequences;
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u32 sequence =
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((u32)(u8)(values[1] - values[0]) << 8) |
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((u32)(u8)(values[2] - values[1]) << 16) |
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((u32)(u8)(values[3] - values[2]) << 24);
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for (usize i = 4; i < values.size(); i++)
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{
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sequence = (sequence >> 8) | ((u32)(u8)(values[i] - values[i - 1]) << 24);
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if (found_sequences.contains(sequence))
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continue;
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MUST(found_sequences.insert(sequence));
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auto it = sequence_to_bananas.find(sequence);
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if (it == sequence_to_bananas.end())
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it = MUST(sequence_to_bananas.insert(sequence, 0));
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it->value += values[i];
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}
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}
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u64 result = 0;
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for (auto [_, bananas] : sequence_to_bananas)
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result = BAN::Math::max(result, bananas);
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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/aoc2024/day22_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("part1: %" PRId64 "\n", part1(fp));
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fseek(fp, 0, SEEK_SET);
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printf("part2: %" PRId64 "\n", part2(fp));
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fclose(fp);
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}
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