birdulon
/
AdventOfCode
1
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

clean up mix amount

This commit is contained in:
Luke Hubmayer-Werner 2022-12-21 14:46:51 +10:30
parent a2b45f1cd8
commit 5b2e3ebaf0
1 changed files with 16 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

24
2022/day20.c
View File

@ -11,7 +11,6 @@ struct list_node {
void mix_right(struct list_node* node, long amount) { void mix_right(struct list_node* node, long amount) {
struct list_node* new_prev = node->next; struct list_node* new_prev = node->next;
amount %= INPUT_LENGTH-1;
// Pop from position // Pop from position
node->prev->next = node->next; node->prev->next = node->next;
node->next->prev = node->prev; node->next->prev = node->prev;
@ -29,7 +28,6 @@ void mix_right(struct list_node* node, long amount) {
void mix_left(struct list_node* node, long amount) { void mix_left(struct list_node* node, long amount) {
struct list_node* new_next = node->prev; struct list_node* new_next = node->prev;
amount %= INPUT_LENGTH-1;
// Pop from position // Pop from position
node->prev->next = node->next; node->prev->next = node->next;
node->next->prev = node->prev; node->next->prev = node->prev;
@ -46,12 +44,22 @@ void mix_left(struct list_node* node, long amount) {
} }
void mix(struct list_node* node) { void mix(struct list_node* node) {
int amount = node->value; int forward_amount = node->value;
if (amount > 0) { int reverse_amount;
mix_right(node, amount); const int mod = INPUT_LENGTH-1;
} else if (amount < 0) { if (forward_amount == 0) return; // Do nothing for 0
mix_left(node, -amount); if (forward_amount > 0) {
} // Do nothing for 0 forward_amount = forward_amount % mod;
reverse_amount = mod - forward_amount;
} else {
reverse_amount = -forward_amount % mod;
forward_amount = mod - reverse_amount;
}
if (forward_amount < reverse_amount) {
mix_right(node, forward_amount);
} else {
mix_left(node, reverse_amount);
}
} }
int main(int argc, char *argv[]) { int main(int argc, char *argv[]) {