Inlägg

#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define ARRAY_LEN(x) (sizeof(x) / sizeof((x)[0]))

int parseInt(const char *str) {
	char *endptr;
	int ret;

	errno = 0;
	ret = strtol(str, &endptr, 10);

	if (errno != 0) {
		perror("Failed to parse string");
		exit(EXIT_FAILURE);
	}

	if (endptr == str) {
		fprintf(stderr, "No digits were found\n");
		exit(EXIT_FAILURE);
	}

	if (*endptr != '\0')
		printf("Warning: further characters after number: \"%s\"\n", endptr);

	return ret;
}

int main(void) {
	char *line = NULL;
	size_t len = 0;
	ssize_t nread;
	int curSum = 0;
	int top[3] = { 0 };

	FILE *fp = fopen("d1_input.txt", "r");
	if (!fp) {
		perror("Failed to open file");
		exit(EXIT_FAILURE);
	}

	while ((nread = getline(&line, &len, fp)) != -1) {
		if (!strcmp(line, "\n")) {
			for (unsigned int i=0; i<ARRAY_LEN(top); i++) {
				if (top[i] <= curSum) {
					memmove(&top[i+1], &top[i], (ARRAY_LEN(top)-i-1)*sizeof(top[0]));
					top[i] = curSum;
					break;
				}
			}

			curSum = 0;
			continue;
		}
		line[nread-1] = '\0';
		curSum += parseInt(line);
	}

	free(line);
	fclose(fp);

	curSum = 0;
	printf("Max calorie sum:  %d\n", top[0]);
	printf("Top calorie sums:");
	for (unsigned int i=0; i<ARRAY_LEN(top); i++) {
		curSum += top[i];
		printf (" %d", top[i]);
	}
	printf("\n");
	printf("Top total sum: %d\n", curSum);

	exit(EXIT_SUCCESS);
}

#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

enum weapon { ROCK = 0, PAPER, SCISSORS };
enum outcome { LOSS = ROCK, TIE = PAPER, WIN = SCISSORS };

const int value[3] = { [ROCK] = 1, [PAPER] = 2, [SCISSORS] = 3 };
const int score[3] = { [LOSS] = 0, [TIE] = 3, [WIN] = 6 };

// Outcome score LUT, first dimension: my weapon, second dimension their weapon
const int outcomeScore[3][3] = { [ROCK]     = { [ROCK] = score[TIE],  [PAPER] = score[LOSS], [SCISSORS] = score[WIN]  },
                                 [PAPER]    = { [ROCK] = score[WIN],  [PAPER] = score[TIE],  [SCISSORS] = score[LOSS] },
                                 [SCISSORS] = { [ROCK] = score[LOSS], [PAPER] = score[WIN],  [SCISSORS] = score[TIE]  },
                               };

// My weapon value LUT for certain outcome, first dimension: outcome, second dimension: their weapon
const int valueGivenOutcome[3][3] = { [LOSS] = { [ROCK] = value[SCISSORS], [PAPER] = value[ROCK],     [SCISSORS] = value[PAPER]    },
                                      [TIE]  = { [ROCK] = value[ROCK],     [PAPER] = value[PAPER],    [SCISSORS] = value[SCISSORS] },
                                      [WIN]  = { [ROCK] = value[PAPER],    [PAPER] = value[SCISSORS], [SCISSORS] = value[ROCK]     },
                                    };

int getWeaponOrOutcomeIdx(char chr) {
	switch (chr) {
		case 'A':
		case 'X':
			return ROCK;
		case 'B':
		case 'Y':
			return PAPER;
		case 'C':
		case 'Z':
			return SCISSORS;
		default:
			fprintf(stderr, "Unknown character: %c\n", chr);
			exit(EXIT_FAILURE);
	}
}

int main(void) {
	char *line = NULL;
	size_t len = 0;
	ssize_t nread;
	int totalScoreP1 = 0;
	int totalScoreP2 = 0;

	FILE *fp = fopen("d2_input.txt", "r");
	if (!fp) {
		perror("Failed to open file");
		exit(EXIT_FAILURE);
	}

	while ((nread = getline(&line, &len, fp)) != -1) {
		enum weapon theirIdx, myIdx;
		char *tok = strtok(line, " \n");
		if (!tok) exit(EXIT_FAILURE);
		theirIdx = getWeaponOrOutcomeIdx(tok[0]);

		tok = strtok(NULL, " \n");
		if (!tok) exit(EXIT_FAILURE);
		myIdx = getWeaponOrOutcomeIdx(tok[0]);

		totalScoreP1 += value[myIdx] + outcomeScore[myIdx][theirIdx];
		totalScoreP2 += valueGivenOutcome[myIdx][theirIdx] + score[myIdx];
	}

	free(line);
	fclose(fp);

	printf("totalScoreP1 = %d\n", totalScoreP1);
	printf("totalScoreP2 = %d\n", totalScoreP2);

	exit(EXIT_SUCCESS);
}

#include <errno.h>
#include <inttypes.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define ARRAY_LEN(x) (sizeof(x) / sizeof((x)[0]))

int getPriority(uint64_t item) {
	int lcase, ucase;

	lcase = ffs(item >> 32);
	ucase = ffsll((item & 0xffffffff) << 26);

	return lcase + ucase;
}

int main(void) {
	char *line = NULL;
	size_t len = 0;
	ssize_t nread;
	uint32_t totalPrio = 0;
	uint32_t totalBadgePrio = 0;

	FILE *fp = fopen("d3_input.txt", "r");
	if (!fp) {
		perror("Failed to open file");
		exit(EXIT_FAILURE);
	}

	while ((nread = getline(&line, &len, fp)) != -1) {
		uint64_t compartment[2] = { 0 };
		uint64_t overlap;
		static uint64_t rucksack[3];
		static int rucksack_cnt = 0;
		nread--;

		for (int i=0; i<nread>>1; i++)
			compartment[0] |= UINT64_C(1)<<(line[i]-'A');

		for (int i=nread>>1; i<nread; i++)
			compartment[1] |= UINT64_C(1)<<(line[i]-'A');

		overlap = compartment[0] & compartment[1];
		totalPrio += getPriority(overlap);

		// Part 2:
		rucksack[rucksack_cnt++] = compartment[0] | compartment[1];
		if (rucksack_cnt == ARRAY_LEN(rucksack)) {
			uint64_t badge = UINT64_MAX;
			for (unsigned int i=0; i<ARRAY_LEN(rucksack); i++)
				badge &= rucksack[i];
			rucksack_cnt = 0;
			totalBadgePrio += getPriority(badge);
		}
	}

	free(line);
	fclose(fp);

	printf("Total prio: %"PRIu32"\n", totalPrio);
	printf("Total badge prio: %"PRIu32"\n", totalBadgePrio);

	exit(EXIT_SUCCESS);
}