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#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#define BUFFER 10000
#define DUP_SIZE 10000
long part_one(FILE *fp)
{
long res = 0;
int player_one[512] = { 0 }, player_two[512] = { 0 };
int one_low = 0, one_high = 0, two_low = 0, two_high = 0;
char *line = NULL;
size_t len;
int paragraph = 0;
int index = 0;
while (getline(&line, &len, fp) != -1) {
if (line[0] == '\n') {
index = 0;
paragraph++;
continue;
} else if (line[0] == 'P') {
continue;
} else {
int num;
sscanf(line, "%d", &num);
if (paragraph == 0)
player_one[index++] = num;
else
player_two[index++] = num;
}
}
free(line);
one_high = two_high = index;
while (1) {
int c1 = player_one[one_low++];
int c2 = player_two[two_low++];
if (!c1 || !c2)
break;
if (c1 > c2) {
player_one[one_high++] = c1;
player_one[one_high++] = c2;
} else {
player_two[two_high++] = c2;
player_two[two_high++] = c1;
}
}
int two_won = one_low == one_high + 1;
int *winner = two_won ? player_two : player_one;
int low = two_won ? two_low : one_low;
int high = two_won ? two_high : one_high;
for (int i = high - low + 1, j = 0; i > 0; i--, j++)
res += i * winner[low + j - 1];
return res;
}
// Returns 0 if one won, 1 if two won
int recursive(int *player_one, int *player_two, int *one_low, int *one_high, int *two_low,
int *two_high, int iter)
{
int one_copy[BUFFER] = { 0 }, two_copy[BUFFER] = { 0 };
memcpy(&one_copy[*one_low], &player_one[*one_low], (*one_high - *one_low) * sizeof(int));
memcpy(&two_copy[*two_low], &player_two[*two_low], (*two_high - *two_low) * sizeof(int));
int dup_ind = 0;
int(*dup_one)[DUP_SIZE] = malloc(DUP_SIZE * BUFFER * sizeof(int));
int(*dup_two)[DUP_SIZE] = malloc(DUP_SIZE * BUFFER * sizeof(int));
while (1) {
// Check for duplicates.. (hashmaps would be nice)
for (int i = 0; i < dup_ind; i++) {
if (!memcmp(dup_one[i], &one_copy[*one_low],
(*one_high - *one_low + 1) * sizeof(int)) ||
!memcmp(dup_two[i], &two_copy[*two_low],
(*two_high - *two_low + 1) * sizeof(int))) {
free(dup_one);
free(dup_two);
return 0;
}
}
memcpy(dup_one[dup_ind], &one_copy[*one_low], (*one_high - *one_low) * sizeof(int));
memcpy(dup_two[dup_ind++], &two_copy[*two_low],
(*two_high - *two_low) * sizeof(int));
if (dup_ind >= DUP_SIZE)
exit(1);
/* for (int *p = &one_copy[*one_low]; *p; p++) */
/* printf("%d ", *p); */
/* printf(" (L1: %d, H1: %d)\n", *one_low, *one_high); */
/* for (int *p = &two_copy[*two_low]; *p; p++) */
/* printf("%d ", *p); */
/* printf(" (L2: %d, H2: %d)\n\n", *two_low, *two_high); */
int c1 = one_copy[(*one_low)++];
int c2 = two_copy[(*two_low)++];
if (!c1 || !c2)
break;
int rec_won = -1;
if (*one_high + 1 - *one_low > c1 && *two_high + 1 - *two_low > c2) {
/* printf("AAH RECURSION: %d %d\n", c1, c2); */
int rec_one_low = *one_low;
int rec_one_high = *one_low + c1;
int rec_two_low = *two_low;
int rec_two_high = *two_low + c2;
rec_won = recursive(one_copy, two_copy, &rec_one_low, &rec_one_high,
&rec_two_low, &rec_two_high, iter + 1);
/* printf("REC: %d\n", rec_won); */
}
if (rec_won == -1) {
if (c1 > c2) {
one_copy[(*one_high)++] = c1;
one_copy[(*one_high)++] = c2;
} else {
two_copy[(*two_high)++] = c2;
two_copy[(*two_high)++] = c1;
}
} else {
if (rec_won) {
two_copy[(*two_high)++] = c2;
two_copy[(*two_high)++] = c1;
} else {
one_copy[(*one_high)++] = c1;
one_copy[(*one_high)++] = c2;
}
}
}
if (iter == 0) {
memcpy(player_one, one_copy, BUFFER);
memcpy(player_two, two_copy, BUFFER);
}
free(dup_one);
free(dup_two);
return one_low != one_high + 1;
}
long part_two(FILE *fp)
{
long res = 0;
int player_one[BUFFER] = { 0 }, player_two[BUFFER] = { 0 };
int one_low = 0, one_high = 0, two_low = 0, two_high = 0;
char *line = NULL;
size_t len;
int paragraph = 0;
int index = 0;
while (getline(&line, &len, fp) != -1) {
if (line[0] == '\n') {
index = 0;
paragraph++;
continue;
} else if (line[0] == 'P') {
continue;
} else {
int num;
sscanf(line, "%d", &num);
if (paragraph == 0)
player_one[index++] = num;
else
player_two[index++] = num;
}
}
free(line);
one_high = two_high = index;
recursive(player_one, player_two, &one_low, &one_high, &two_low, &two_high, 0);
int two_won = one_low == one_high + 1;
int *winner = two_won ? player_two : player_one;
int low = two_won ? two_low : one_low;
int high = two_won ? two_high : one_high;
for (int i = high - low + 1, j = 0; i > 0; i--, j++)
res += i * winner[low + j - 1];
return res;
}
int main(int argc, char *argv[])
{
FILE *fp = fopen("input", "r");
if (!fp)
exit(EXIT_FAILURE);
clock_t tic = clock();
printf("%lu\n", part_one(fp));
rewind(fp);
printf("%lu\n", part_two(fp));
clock_t toc = clock();
printf("TIME: %f seconds\n", (double)(toc - tic) / CLOCKS_PER_SEC);
fclose(fp);
return 0;
}
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