aoc_omni/c/2024/1/historian_hysteria.c

53 lines
1002 B
C

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "../../lib/aoc.h"
// TODO figure this out dynamically
#define ARRAY_SIZE 1000
int main() {
char *line;
int left[ARRAY_SIZE];
int right[ARRAY_SIZE];
int index = 0;
while ((line = aoc_read_line()) != NULL) {
int l, r;
sscanf(line, "%d %d", &l, &r);
left[index] = l;
right[index] = r;
index++;
}
qsort(left, ARRAY_SIZE, sizeof(int), aoc_sort_int);
qsort(right, ARRAY_SIZE, sizeof(int), aoc_sort_int);
int sum = 0;
for (int i = 0; i < ARRAY_SIZE; i++) {
sum += abs(left[i] - right[i]);
}
printf("Part 1: %d\n", sum);
int similarity_score = 0;
int j = 0;
for (int i = 0; i < ARRAY_SIZE; i++) {
int right_count = 0;
for (; j < ARRAY_SIZE; j++) {
if (left[i] == right[j]) right_count++;
else if (left[i] < right[j]) break;
}
similarity_score += (left[i] * right_count);
}
printf("Part 2: %d\n", similarity_score);
aoc_free();
return 0;
}