day 15 part two donE

diff --git a/15b.c b/15b.c
index 65d8081..26881a3 100644 (file)
--- a/15b.c
+++ b/15b.c
@@ -1,14 +1,13 @@
 #include <stdio.h>
-#include <stdbool.h>
-#include <stdlib.h>
 #include <limits.h>
-#include <string.h>
-#include <search.h>
+#include <uthash.h>
 
-#define min(a, b) ((a) < (b) ? (a) : (b))
-#define MFAC 1
+#define MFAC 5
 
 struct point { int x; int y; };
+#define pnt(px, py) ((struct point){.x=(px), .y=(py)})
+struct q { struct point key; UT_hash_handle hh; };
+int dist[100*MFAC][100*MFAC];
 
 int grid[100][100] = {0};
 int maxx = 0;
@@ -24,21 +23,11 @@ int get_grid(int x, int y)
        return r;
 }
 
-int dist[100*MFAC][100*MFAC];
-
-int mindist(const void *l, const void *r)
-{
-       struct point lp = *(const struct point *)l;
-       struct point rp = *(const struct point *)r;
-       return dist[rp.y][rp.x]-dist[lp.y][lp.x];
-}
-
-struct point *is_in_q(struct point *q, size_t nq, int x, int y)
+int qcmp(const void *l, const void *r)
 {
-       for (size_t i = 0; i<nq; i++)
-               if (q[i].x == x && q[i].y == y)
-                       return q+i;
-       return NULL;
+       const struct q *lp = (const struct q *)l;
+       const struct q *rp = (const struct q *)r;
+       return dist[lp->key.y][lp->key.x]-dist[rp->key.y][rp->key.x];
 }
 
 int main()
@@ -54,52 +43,42 @@ int main()
                }
        }
 
-       struct point q[100*MFAC*100*MFAC];
-       size_t qp = 0;
-       struct point prev[100*MFAC][100*MFAC];
+       struct q *q = NULL;
 
-//     grid[0][0] = 0;
        for (int y = 0; y<maxy*MFAC; y++) {
                for (int x = 0; x<maxx*MFAC; x++) {
                        dist[y][x] = INT_MAX;
-                       prev[y][x] = (struct point){.x=-1, .y=-1};
-                       q[qp++] = (struct point){.x=x, .y=y};
+                       struct q *i = malloc(sizeof(struct q));
+                       i->key = pnt(x, y);
+                       HASH_ADD(hh, q, key, sizeof(struct point), i);
                }
        }
        dist[0][0] = 0;
+       HASH_SRT(hh, q, qcmp);
 
-       while (qp > 0) {
-//             printf("size of q: %lu\n", qp);
-               qsort(q, qp, sizeof(struct point), mindist);
-               qp--;
-               struct point u = q[qp];
+       while (q != NULL) {
+               struct point u = q->key;
+               HASH_DELETE(hh, q, q);
                for (int dy = -1; dy <= 1; dy++) {
                        for (int dx = -1; dx <= 1; dx++) {
                                //Skip diagonal neigbours
-                               if (dx == dy)
+                               if (abs(dx) == abs(dy))
                                        continue;
                                //check if v is in Q
-                               struct point *v = is_in_q(&q[0], qp, u.x+dx, u.y+dy);
+                               struct q *v;
+                               HASH_FIND(hh, q, &pnt(u.x+dx, u.y+dy), sizeof(struct point), v);
                                if (v == NULL)
                                        continue;
                                //Update dist if necessary
-                               int alt = dist[u.y][u.x] + get_grid(v->x, v->y);
-                               if (alt < dist[v->y][v->x]) {
-                                       dist[v->y][v->x] = alt;
-                                       prev[v->y][v->x] = u;
+                               int alt = dist[u.y][u.x] + get_grid(v->key.x, v->key.y);
+                               if (alt < dist[v->key.y][v->key.x]) {
+                                       dist[v->key.y][v->key.x] = alt;
+                                       HASH_DELETE(hh, q, v);
+                                       HASH_ADD_INORDER(hh, q, key, sizeof(struct point), v, qcmp);
                                }
                        }
                }
        }
 
-       printf("path: ");
-       struct point u = {.y=maxy*MFAC-1, .x=maxx*MFAC-1};
-       do {
-               u = prev[u.y][u.x];
-               printf("%d,%d ", u.x, u.y);
-       } while (u.x!= 0 && u.y != 0);
-
-       printf("\n");
-
        printf("%d\n", dist[maxy*MFAC-1][maxx*MFAC-1]);
 }