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#include <stdio.h>
#include <stdlib.h>
#include <time.h>
static int LENGTH = 0;
int part_one(int *data)
{
int prev = 0, three = 1, one = 0;
for (int i = 0; i < LENGTH; i++) {
if (data[i] == 0)
continue;
if (data[i] - prev == 3)
three++;
else
one++;
prev = data[i];
}
return one * three;
}
#define COND(i, o) ((i) + (o) < LENGTH && *(cur + (o)) - *cur <= 3)
long part_two(int *data)
{
long a = 1;
long b = 0;
long c = 0;
int *cur = &data[LENGTH - 1];
while (cur-- != &data[0]) {
int i = cur - data;
long next = (COND(i, 1) ? a : 0) + (COND(i, 2) ? b : 0) + (COND(i, 3) ? c : 0);
c = b;
b = a;
a = next;
}
return a;
}
int cmp(const void *a, const void *b)
{
int int_a = *((int *)a);
int int_b = *((int *)b);
if (int_a == int_b)
return 0;
else if (int_a < int_b)
return -1;
else
return 1;
}
int *to_int(FILE *fp, int *arr)
{
int d = 0, i = 0;
while (fscanf(fp, "%d\n", &d) != EOF)
arr[i++] = d;
LENGTH = i + 1;
return arr;
}
int main()
{
FILE *fp = fopen("input", "r");
if (!fp)
exit(EXIT_FAILURE);
int data[128] = { 0 };
to_int(fp, data);
qsort(data, LENGTH, sizeof(int), cmp);
clock_t tic = clock();
printf("%d\n", part_one(data));
printf("%lu\n", part_two(data));
clock_t toc = clock();
printf("TIME: %f seconds\n", (double)(toc - tic) / CLOCKS_PER_SEC);
fclose(fp);
return 0;
}
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