forked from Bananymous/banan-os
119 lines
2.1 KiB
C++
119 lines
2.1 KiB
C++
#include <BAN/StringView.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 is_safe(i64 curr, i64 prev, bool inc)
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{
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i64 abs_diff = BAN::Math::abs(curr - prev);
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if (abs_diff == 0 || abs_diff > 3)
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return false;
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if ((curr > prev) != inc)
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return false;
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return true;
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}
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i64 part1(FILE* fp)
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{
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i64 ret = 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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auto strs = MUST(BAN::StringView(buffer).split(' '));
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ASSERT(strs.size() >= 2);
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i64 prev = atoll(strs[0].data());
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i64 curr = atoll(strs[1].data());
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const bool inc = (curr > prev);
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if (!is_safe(curr, prev, inc))
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continue;
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bool safe = true;
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for (size_t i = 2; i < strs.size() && safe; i++)
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{
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prev = curr;
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curr = atoll(strs[i].data());
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safe = is_safe(curr, prev, inc);
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}
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ret += safe;
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}
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return ret;
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}
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i64 part2(FILE* fp)
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{
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i64 ret = 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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auto strs = MUST(BAN::StringView(buffer).split(' '));
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ASSERT(strs.size() >= 3);
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for (size_t skip_idx = 0; skip_idx < strs.size(); skip_idx++)
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{
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i64 prev = atoll(strs[0 + (skip_idx <= 0)].data());
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i64 curr = atoll(strs[1 + (skip_idx <= 1)].data());
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const bool inc = (curr > prev);
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if (!is_safe(curr, prev, inc))
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continue;
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bool safe = true;
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for (size_t i = 2 + (skip_idx <= 2); i < strs.size() && safe; i++)
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{
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if (i == skip_idx)
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continue;
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prev = curr;
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curr = atoll(strs[i].data());
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safe = is_safe(curr, prev, inc);
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}
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if (!safe)
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continue;
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ret++;
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break;
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}
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}
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return ret;
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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/day2_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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