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adventofcode2024
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day 6 reduce state size

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magical 2024-12-06 05:51:15 +00:00
parent 67cd627138
commit ece6ff1139
1 changed files with 5 additions and 5 deletions
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10
day06/sol.c
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@ -144,20 +144,20 @@ int solve(struct grid *g) {
}
// returns whether the chosen grid will cause the guard to get stuck in a loop
bool loops(struct grid *g, struct point start, uint16_t* state) {
bool loops(struct grid *g, struct point start, uint8_t* state) {
int x = start.x;
int y = start.y;
int dx = 0, dy = -1; // up
int stride = g->x;
//printf("loops(%d,%d)\n", x,y);
while(inbounds(g, x, y)) {
uint16_t dir = 15;
uint8_t dir = 15;
if (dx == 1) { dir = 1; }
else if (dx == -1) { dir = 2; }
else if (dy == 1) { dir = 4; }
else if (dy == -1) { dir = 8; }
uint16_t *s = &state[y*stride + x];
uint8_t *s = &state[y*stride + x];
if ((*s & dir) != 0) {
// revisited a state, loop!
return true;
@ -183,8 +183,8 @@ int solve2(struct grid *g) {
int count = 0;
int ox, oy; // obstacle coords
struct point p = startingPoint(g);
size_t state_size = g->x * g->y * sizeof(uint16_t);
uint16_t *state = xrealloc(NULL, state_size);
size_t state_size = g->x * g->y * sizeof(uint8_t);
uint8_t *state = xrealloc(NULL, state_size);
for (oy = 0; oy < g->y; oy++)
for (ox = 0; ox < g->x; ox++) {
int c = g->A[oy][ox];