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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
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24
2022/day20.c
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@ -11,7 +11,6 @@ struct list_node {
void mix_right(struct list_node* node, long amount) {
struct list_node* new_prev = node->next;
amount %= INPUT_LENGTH-1;
// Pop from position
node->prev->next = node->next;
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) {
struct list_node* new_next = node->prev;
amount %= INPUT_LENGTH-1;
// Pop from position
node->prev->next = node->next;
node->next->prev = node->prev;
@ -46,12 +44,22 @@ void mix_left(struct list_node* node, long amount) {
}
void mix(struct list_node* node) {
int amount = node->value;
if (amount > 0) {
mix_right(node, amount);
} else if (amount < 0) {
mix_left(node, -amount);
} // Do nothing for 0
int forward_amount = node->value;
int reverse_amount;
const int mod = INPUT_LENGTH-1;
if (forward_amount == 0) return; // Do nothing for 0
if (forward_amount > 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[]) {