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day19: find common beacons between two scanners

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This commit is contained in:
Bruno Raoult
2022-01-14 15:10:45 +01:00
parent e3382ef3dd
commit 645188216e
1 changed files with 42 additions and 13 deletions
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55
2021/day19/aoc-c.c
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@@ -35,13 +35,14 @@
#define MAX_DISTANCES ((MAX_BEACONS - 1) * MAX_BEACONS) #define MAX_DISTANCES ((MAX_BEACONS - 1) * MAX_BEACONS)
typedef struct beacon { typedef struct beacon {
int x, y, z; int x, y, z; /* beacon coordinates */
struct list_head list_beacons; uint count; /* common scanner distance count */
//struct list_head list_beacons;
} beacon_t; } beacon_t;
typedef struct dist { typedef struct dist {
u64 dist; uint dist; /* square distance */
int b1, b2; int b1, b2; /* beacons */
} dist_t; } dist_t;
typedef struct scanner { typedef struct scanner {
@@ -65,7 +66,7 @@ static void scanners_print_dists()
log(1, "scanner %d:\n", i); log(1, "scanner %d:\n", i);
for (int j = 0; j < scanners[i].ndists; ++j) { for (int j = 0; j < scanners[i].ndists; ++j) {
cur = &scanners[i].dists[j]; cur = &scanners[i].dists[j];
log(1, "\t%d : %d,%d\n", cur->dist, cur->b1, cur->b2); log(1, "\t%u : %d,%d\n", cur->dist, cur->b1, cur->b2);
} }
log(1, "\n"); log(1, "\n");
} }
@@ -131,13 +132,25 @@ static void mergesort(array, left, right)
static int count_common_distances(scanner_t *s1, scanner_t *s2) static int count_common_distances(scanner_t *s1, scanner_t *s2)
{ {
dist_t *d1 = s1->dists, *d2 = s2->dists; dist_t *d1 = s1->dists, *d2 = s2->dists;
int cur1 = 0, cur2 = 0; int cur1 = 0, cur2 = 0, i;
uint count = 0; uint count = 0;
beacon_t *beacon1 = s1->beacons, *beacon2 = s2->beacons;
log_f(1, "(%d, %d): ", s1 - scanners, s2 - scanners); /* initialize s1 and s2 beacons count
*/
for (i = 0; i < s1->nbeacons; ++i)
beacon1[i].count = 0;
for (i = 0; i < s2->nbeacons; ++i)
beacon2[i].count = 0;
log_f(1, "(%ld, %ld): ", s1 - scanners, s2 - scanners);
while (cur1 < s1->ndists && cur2 < s2->ndists) { while (cur1 < s1->ndists && cur2 < s2->ndists) {
if (d1[cur1].dist == d2[cur2].dist) { if (d1[cur1].dist == d2[cur2].dist) {
log_i(3, " %ld", d1[cur1].dist); log(1, " (%d,%d)=%u", cur1, cur2, d1[cur1].dist);
++beacon1[d1[cur1].b1].count;
++beacon1[d1[cur1].b2].count;
++beacon2[d2[cur2].b1].count;
++beacon2[d2[cur2].b2].count;
++count; ++count;
++cur1; ++cur1;
++cur2; ++cur2;
@@ -173,7 +186,7 @@ static void calc_square_distances()
(b1->z - b2->z) * (b1->z - b2->z); (b1->z - b2->z) * (b1->z - b2->z);
scanner->dists[scanner->ndists].dist = dist; scanner->dists[scanner->ndists].dist = dist;
scanner->ndists++; scanner->ndists++;
log(5, "\tdist(%d/%d) = %lu\n", log(5, "\tdist(%d/%d) = %u\n",
j, k, j, k,
dist); dist);
} }
@@ -225,10 +238,26 @@ static int read_lines()
free(buf); free(buf);
scanners_print(); scanners_print();
calc_square_distances(); calc_square_distances();
for (int i = 0; i < nscanners - 1; ++i) for (int i = 0; i < nscanners - 1; ++i) {
for (int j = i + 1; j < nscanners; ++j) for (int j = i + 1; j < nscanners; ++j) {
log(1, "common(%d, %d) = %d\n", i, j, int count = count_common_distances(scanners + i, scanners + j);
count_common_distances(scanners + i, scanners + j)); if (count >= 66) {
log(1, "common(%d, %d) = %d\n", i, j, count);
for (int k = 0; k < scanners[i].nbeacons; ++k) {
beacon_t *beacon = scanners[i].beacons + k;
if (beacon->count >= 11)
log(1, "s1(%d, %d, %d): %d\n", beacon->x, beacon->y,
beacon->z, beacon->count);
}
for (int k = 0; k < scanners[j].nbeacons; ++k) {
beacon_t *beacon = scanners[j].beacons + k;
if (beacon->count >= 11)
log(1, "s2(%d, %d, %d): %d\n", beacon->x, beacon->y,
beacon->z, beacon->count);
}
}
}
}
return nscanners; return nscanners;
} }