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#include <err.h>
#include <stdio.h>
#include <stdlib.h>
#define BUFFER 200
int
main(void)
{
int nums[BUFFER];
FILE *fp;
if (!(fp = fopen("input", "r")))
err(EXIT_FAILURE, "fopen");
for (int i = 0; i < BUFFER; i++)
fscanf(fp, "%d", &nums[i]);
fclose(fp);
/* Inefficient, but small sample size so it's fine */
for (int i = 0; i < BUFFER - 1; i++) {
for (int j = i + 1; j < BUFFER; j++) {
#ifdef PART2
for (int k = j + 1; k < BUFFER; k++) {
if (nums[i] + nums[j] + nums[k] == 2020) {
printf("%d\n", nums[i] * nums[j] * nums[k]);
return EXIT_SUCCESS;
}
}
#else
if (nums[i] + nums[j] == 2020) {
printf("%d\n", nums[i] * nums[j]);
return EXIT_SUCCESS;
}
#endif
}
}
}
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