aoc2024: Implement day24 solution
This is kinda weird and specific to my input but it works xD
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d035068982
commit
3607e2e759
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@ -22,6 +22,7 @@ set(AOC2024_PROJECTS
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day21
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day22
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day23
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day24
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full
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)
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@ -0,0 +1,9 @@
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set(SOURCES
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main.cpp
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)
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add_executable(aoc2024_day24 ${SOURCES})
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banan_link_library(aoc2024_day24 ban)
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banan_link_library(aoc2024_day24 libc)
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install(TARGETS aoc2024_day24 OPTIONAL)
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@ -0,0 +1,296 @@
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#include <BAN/HashMap.h>
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#include <BAN/HashSet.h>
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#include <BAN/Sort.h>
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#include <BAN/String.h>
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#include <BAN/StringView.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 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 u32 name_to_u32(BAN::StringView name)
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{
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ASSERT(name.size() == 3);
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return ((u32)name[0] << 16) | ((u32)name[1] << 8) | ((u32)name[2] << 0);
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}
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static BAN::String u32_to_name(u32 val)
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{
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BAN::String result;
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MUST(result.push_back(val >> 16));
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MUST(result.push_back(val >> 8));
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MUST(result.push_back(val >> 0));
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return result;
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}
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struct Op
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{
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enum { OR, AND, XOR } type { OR };
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u32 src1 { 0 };
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u32 src2 { 0 };
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u32 dst { 0 };
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};
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struct ParseInputResult
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{
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BAN::HashMap<u32, u8> wires;
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BAN::Vector<Op> ops;
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};
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static ParseInputResult parse_input(FILE* fp)
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{
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char buffer[128];
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BAN::HashMap<u32, u8> wires;
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while (fgets(buffer, sizeof(buffer), fp))
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{
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if (buffer[0] == '\n')
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break;
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MUST(wires.insert(name_to_u32(BAN::StringView(buffer).substring(0, 3)), buffer[5] - '0'));
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}
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BAN::Vector<Op> ops;
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while (fgets(buffer, sizeof(buffer), fp))
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{
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auto parts = MUST(BAN::StringView(buffer).split([](char c) -> bool { return isspace(c); }));
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MUST(ops.emplace_back(
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(parts[1] == "OR"_sv) ? Op::OR : (parts[1] == "AND"_sv) ? Op::AND : Op::XOR,
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name_to_u32(parts[0]),
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name_to_u32(parts[2]),
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name_to_u32(parts[4])
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));
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}
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return {
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.wires = BAN::move(wires),
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.ops = BAN::move(ops),
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};
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}
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i64 part1(FILE* fp)
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{
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auto [wires, ops] = parse_input(fp);
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BAN::HashSet<u32> defined_wires;
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for (const auto [wire, _] : wires)
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MUST(defined_wires.insert(wire));
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usize ops_done_count = 0;
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BAN::Vector<u8> ops_done_map;
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MUST(ops_done_map.resize((ops.size() + 7) / 8, 0));
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while (ops_done_count < ops.size())
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{
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for (usize i = 0; i < ops.size(); i++)
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{
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if (ops_done_map[i / 8] & (1 << (i % 8)))
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continue;
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if (!defined_wires.contains(ops[i].src1) || !defined_wires.contains(ops[i].src2))
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continue;
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const u8 src1 = wires[ops[i].src1];
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const u8 src2 = wires[ops[i].src2];
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u8 val = 0;
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switch (ops[i].type)
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{
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case Op::OR: val = src1 | src2; break;
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case Op::AND: val = src1 & src2; break;
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case Op::XOR: val = src1 ^ src2; break;
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}
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MUST(wires.insert_or_assign(ops[i].dst, val));
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MUST(defined_wires.insert(ops[i].dst));
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ops_done_count++;
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ops_done_map[i / 8] |= (1 << (i % 8));
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}
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}
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u64 result = 0;
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for (usize bit = 0; bit < 64; bit++)
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{
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char name[4];
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name[0] = 'z';
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name[1] = (bit / 10) + '0';
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name[2] = (bit % 10) + '0';
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name[3] = '\0';
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auto it = wires.find(name_to_u32(name));
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if (it == wires.end())
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break;
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result |= (u64)it->value << bit;
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}
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return result;
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}
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static bool has_sources(Op op, u32 src1, u32 src2)
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{
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if (op.src1 == src1 && op.src2 == src2)
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return true;
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if (op.src1 == src2 && op.src2 == src1)
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return true;
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return false;
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}
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struct u32Triplet
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{
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u32 op_and, op_xor, op_or;
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};
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static u32Triplet find_ops(const BAN::Vector<Op>& ops, u32 src1, u32 src2)
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{
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u32 op_and = 0, op_xor = 0, op_or = 0;
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for (auto op : ops)
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{
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if (!has_sources(op, src1, src2))
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continue;
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switch (op.type)
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{
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case Op::AND: op_and = op.dst; break;
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case Op::XOR: op_xor = op.dst; break;
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case Op::OR: op_or = op.dst; break;
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}
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}
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return { op_and, op_xor, op_or };
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}
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BAN::String part2(FILE* fp)
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{
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auto [wires, ops] = parse_input(fp);
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BAN::Vector<u32> swapped;
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u32 carry = 0;
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for (usize bit = 0; bit < 64; bit++)
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{
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dprintln("bit {}", bit);
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char name[4];
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name[1] = (bit / 10) + '0';
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name[2] = (bit % 10) + '0';
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name[3] = '\0';
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name[0] = 'x';
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const u32 src1 = name_to_u32(name);
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name[0] = 'y';
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const u32 src2 = name_to_u32(name);
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name[0] = 'z';
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const u32 dst = name_to_u32(name);
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auto [src_and, src_xor, _1] = find_ops(ops, src1, src2);
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if (!src_and)
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break;
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ASSERT(src_xor);
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if (bit == 0)
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{
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carry = src_and;
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continue;
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}
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auto [dst_and, dst_xor, _2] = find_ops(ops, carry, src_xor);
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if (dst_xor == 0 && dst_and == 0)
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{
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dwarnln("swapped src xor, src and");
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MUST(swapped.push_back(src_xor));
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MUST(swapped.push_back(src_and));
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BAN::swap(src_xor, src_and);
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auto [tmp_and, tmp_xor, _] = find_ops(ops, carry, src_xor);
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dst_and = tmp_and;
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dst_xor = tmp_xor;
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}
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else if (dst_xor != dst)
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{
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if (dst_and == dst)
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{
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dwarnln("swapped dst xor, dst and");
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MUST(swapped.push_back(dst_xor));
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MUST(swapped.push_back(dst_and));
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BAN::swap(dst_xor, dst_and);
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}
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else if (src_and == dst)
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{
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dwarnln("swapped src and, dst xor");
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MUST(swapped.push_back(src_and));
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MUST(swapped.push_back(dst_xor));
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BAN::swap(src_and, dst_xor);
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}
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else if (src_xor == dst)
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{
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dwarnln("swapped src xor, dst xor");
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MUST(swapped.push_back(src_xor));
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MUST(swapped.push_back(dst_xor));
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BAN::swap(src_and, dst_xor);
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}
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else
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{
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auto [_1, _2, tmp_or] = find_ops(ops, src_and, dst_and);
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if (tmp_or == dst)
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{
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dwarnln("swapped carry, dst xor");
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MUST(swapped.push_back(dst_xor));
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MUST(swapped.push_back(tmp_or));
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carry = dst_xor;
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continue;
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}
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else
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{
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dwarnln("invalid ({}, {}, {})", u32_to_name(dst_xor), u32_to_name(dst_and), u32_to_name(dst));
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ASSERT_NOT_REACHED();
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}
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}
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}
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auto [_3, _4, tmp_or] = find_ops(ops, src_and, dst_and);
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carry = tmp_or;
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}
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ASSERT(swapped.size() == 8);
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BAN::sort::sort(swapped.begin(), swapped.end());
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BAN::String result;
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for (const auto& swap : swapped)
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MUST(result.append(MUST(BAN::String::formatted("{},", u32_to_name(swap)))));
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result.pop_back();
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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/day24_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: %s\n", part2(fp).data());
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fclose(fp);
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}
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