90 lines
3 KiB
C
90 lines
3 KiB
C
#include <stdio.h>
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#include <string.h>
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#include <stdlib.h>
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#include <ctype.h>
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#include <stdbool.h>
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typedef struct {
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int line;
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int index;
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int values[9];
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} star;
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int main() {
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int LINE_LENGTH = 140;
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FILE *inputfile = fopen("./input", "r");
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char line[2048] = { 0 };
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size_t len = 0;
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ssize_t read;
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if (inputfile == NULL) {
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printf("Input file not found. Exiting.");
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exit(1);
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}
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char **lines = malloc(sizeof(char *) * LINE_LENGTH);
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int line_count = 0;
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while (fgets(line, 1024, inputfile)) {
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lines[line_count] = malloc(sizeof(char) * 2048);
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strcpy(lines[line_count], line);
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line_count++;
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}
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int range[3] = { -1, 0, 1 };
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star *gears = malloc(sizeof(star) * 4096);
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int gear_count = 0;
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int answer = 0;
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for (int i = 0; i < LINE_LENGTH; i++) {
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int n = 0;
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char *line = lines[i];
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line[strlen(line) - 1] = '\0';
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bool havegear = false;
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star gear = (star) { 0, 0 };
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for (int j = 0; j < strlen(line); j++) {
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if (isdigit(line[j]) != 0) {
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n = n * 10 + line[j] - '0';
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for (int ii = 0; ii < 3; ii++) {
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for (int jj = 0; jj < 3; jj++) {
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if (i + range[ii] >= 0 && i + range[ii] < LINE_LENGTH && j + range[jj] >= 0 && j + range[jj] < strlen(lines[i])) {
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char cc = lines[i + range[ii]][j + range[jj]];
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if (cc != '.' && isdigit(cc) == 0 && cc == '*') {
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gear = (star) { i + range[ii], j + range[jj], {} };
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havegear = true;
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}
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}
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}
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}
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}
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if (j == strlen(lines[i]) - 1 || isdigit(line[j]) == 0) {
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if (havegear) {
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int gearcounter = 0;
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int found_i = -1;
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for (int k = 0; k < gear_count; k++) {
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if (gears[k].line == gear.line && gears[k].index == gear.index) {
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found_i = k;
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break;
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}
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}
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if (found_i == -1) {
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gears[gear_count] = gear;
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gears[gear_count].values[0] = n;
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gear_count++;
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} else {
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int length = 0;
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for (int k = 0; k < 9; k++) {
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if (gears[found_i].values[k] != 0) {
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length++;
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}
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}
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gears[found_i].values[length] = n;
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length += 1;
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if (length == 2) {
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answer += gears[found_i].values[0] * n;
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}
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}
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havegear = false;
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}
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n = 0;
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}
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}
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}
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printf("Sum: %d\n", answer);
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}
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