forked from Bananymous/banan-os
107 lines
2.0 KiB
C++
107 lines
2.0 KiB
C++
#include <BAN/StringView.h>
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#include <BAN/String.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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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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bool check_if_valid(const BAN::Vector<u64>& vals, size_t idx, u64 curr, bool concat)
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{
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// NOTE: This does not apply in general case, but puzzle input
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// does not contain zeros or negative numbers
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if (curr > vals[0])
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return false;
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if (idx >= vals.size())
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return curr == vals[0];
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if (check_if_valid(vals, idx + 1, curr + vals[idx], concat))
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return true;
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if (check_if_valid(vals, idx + 1, curr * vals[idx], concat))
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return true;
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if (!concat)
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return false;
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u64 mult = 1;
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while (mult <= vals[idx])
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mult *= 10;
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return check_if_valid(vals, idx + 1, curr * mult + vals[idx], concat);
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}
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i64 part1(FILE* fp)
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{
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i64 result = 0;
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char buffer[1024];
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while (fgets(buffer, sizeof(buffer), fp))
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{
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auto strs = MUST(BAN::StringView(buffer).split(' '));
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if (strs.empty())
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break;
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BAN::Vector<u64> vals;
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for (auto str : strs)
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MUST(vals.push_back(atoll(str.data())));
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if (check_if_valid(vals, 2, vals[1], false))
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result += vals[0];
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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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i64 result = 0;
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char buffer[1024];
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while (fgets(buffer, sizeof(buffer), fp))
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{
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auto strs = MUST(BAN::StringView(buffer).split(' '));
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if (strs.empty())
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break;
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BAN::Vector<u64> vals;
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for (auto str : strs)
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MUST(vals.push_back(atoll(str.data())));
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if (check_if_valid(vals, 2, vals[1], true))
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result += vals[0];
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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/aoc2024/day7_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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