diff --git a/day15/beacon b/day15/beacon new file mode 100755 index 0000000..0172eef Binary files /dev/null and b/day15/beacon differ diff --git a/day15/beacon.c b/day15/beacon.c new file mode 100644 index 0000000..d99f6ea --- /dev/null +++ b/day15/beacon.c @@ -0,0 +1,229 @@ +#include +#include +#include +#include + +#define BUFFER_SIZE 128 +#define MAX_SENSORS 128 +#define MAX_RANGES 128 +#define Y_ROW 2000000L +#define MIN_YPOS 0L +#define MAX_YPOS 4000000L +#define XTUNING 4000000ULL + +#define max(a,b) (a >= b ? a : b) +#define min(a,b) (a <= b ? a : b) +#define abs(v) ((v) < 0 ? (-1) * (v) : (v)) + +typedef struct sensor { + long x; + long y; + long beaconX; + long beaconY; + long radius; +} SENSOR; + +long dist(long, long, long, long); +int exists(long [], int, long); +unsigned overlap(long, long, long, long); + +int main() { + char buf[BUFFER_SIZE], *p, c; + memset(buf, 0, BUFFER_SIZE); + p = buf; + SENSOR sensors[MAX_SENSORS], tmp; + int sensor_count = 0; + + while ((c = getchar()) != EOF) { + *p++ = c; + if (c == '\n') { + sscanf(buf, "Sensor at x=%li, y=%li: closest beacon is at x=%li, y=%li", &tmp.x, &tmp.y, &tmp.beaconX, &tmp.beaconY); + tmp.radius = dist(tmp.x, tmp.y, tmp.beaconX, tmp.beaconY); + sensors[sensor_count] = tmp; + sensor_count++; + memset(buf, 0, BUFFER_SIZE); + p = buf; + } + } + + // Scan every row in the given territory + for (long jk = MIN_YPOS; jk < MAX_YPOS; jk++) { + // Save the range for each sensor + long (*scanned)[2]; + scanned = (long(*)[2])malloc(sensor_count * sizeof(long[2])); + memset(scanned, 0, sensor_count * sizeof(long[2])); + unsigned sum = 0; + + // Find all scanned in y=jk + for (int i = 0; i < sensor_count; i++) { + // Not in range + if (abs(sensors[i].y - jk) > sensors[i].radius) { + continue; + } + + unsigned tmp = (sensors[i].radius - abs(sensors[i].y - jk)); + scanned[i][0] = sensors[i].x - tmp; + scanned[i][1] = sensors[i].x + tmp; + } + + long (*ranges)[2]; + ranges = (long(*)[2])malloc(MAX_RANGES * sizeof(long[2])); + memset(ranges, 0, MAX_RANGES * sizeof(long[2])); + int range_count = 0; + // Count scanned and remove overlaps + for (int i = 0; i < sensor_count; i++) { + long sections[16][2]; + int section_count = 0; + sections[0][0] = scanned[i][0]; + sections[0][1] = scanned[i][1]; + section_count++; + for (int j = 0; j < range_count; j++) { + for (int k = 0; k < section_count; k++) { + // Not overlapping + if (sections[k][0] > ranges[j][1] || sections[k][1] < ranges[j][0]) { + continue; + } + + // fully covered + else if (sections[k][0] >= ranges[j][0] && sections[k][1] <= ranges[j][1]) { + for (int l = k; l < section_count - 1; l++) { + sections[l][0] = sections[l+1][0]; + sections[l][1] = sections[l+1][1]; + } + section_count--; + break; + } + + // Inverse covered splits section to two + else if (sections[k][0] < ranges[j][0] && sections[k][1] > ranges[j][1]) { + // Push everything forward + for (int l = section_count; l > k + 1; l--) { + sections[l][0] = sections[l-1][0]; + sections[l][1] = sections[l-1][1]; + } + section_count++; + sections[k+1][1] = sections[k][1]; + sections[k][1] = ranges[j][0] - 1; + sections[k+1][0] = ranges[j][1] + 1; + } + + // Left hook + else if (sections[k][0] < ranges[j][0] && sections[k][1] <= ranges[j][1]) { + sections[k][1] = ranges[j][0] - 1; + } + + // Right hook + else if (sections[k][0] >= ranges[j][0] && sections[k][1] > ranges[j][1]) { + sections[k][0] = ranges[j][1] + 1; + } + } + } + for (int j = 0; j < section_count; j++) { + ranges[range_count][0] = sections[j][0]; + ranges[range_count][1] = sections[j][1]; + range_count++; + } + } + + //printf("OPOPOP\n"); + + int changeCount = 0; + // Combine ranges + do { + changeCount = 0; + for (int i = 0; i < range_count; i++) { + for (int j = i + 1; j < range_count; j++) { + if (ranges[i][0] == ranges[j][1] + 1) { + ranges[i][0] = ranges[j][0]; + for (int k = j; k < range_count - 1; k++) { + ranges[k][0] = ranges[k+1][0]; + ranges[k][1] = ranges[k+1][1]; + } + range_count--; + changeCount++; + } else if (ranges[i][1] + 1 == ranges[j][0]) { + ranges[i][1] = ranges[j][1]; + for (int k = j; k < range_count - 1; k++) { + ranges[k][0] = ranges[k+1][0]; + ranges[k][1] = ranges[k+1][1]; + } + range_count--; + changeCount++; + } + } + } + } while (changeCount != 0); + + for (int i = 0; i < range_count; i++) { + //printf("[%li,%li]\n", ranges[i][0], ranges[i][1]); + sum += ranges[i][1] - ranges[i][0] + 1; + } + + // I don't really understand why, but we also have to exclude beacons + long beaconInWay[32]; + int beaconInWayCount = 0; + for (int i = 0; i < sensor_count; i++) { + int skip = 0; + if (sensors[i].beaconY != jk) { + continue; + } + + for (int k = 0; k < beaconInWayCount; k++) { + if (beaconInWay[k] == sensors[i].beaconX) { + skip = 1; + break; + } + } + + if (skip) { + continue; + } + + for (int j = 0; j < range_count; j++) { + if (sensors[i].beaconX >= ranges[j][0] && sensors[i].beaconX <= ranges[j][1]) { + beaconInWay[beaconInWayCount] = sensors[i].beaconX; + beaconInWayCount++; + sum -= 1; + } + } + } + + // Finally print the results + if (jk == Y_ROW) { + printf("Part one: %u\n", sum); + } + + // Second part + for (int i = 0; i < range_count; i++) { + if (ranges[i][0] > MIN_YPOS && ranges[i][0] <= MAX_YPOS) { + printf("X: %li, Y: %li\n", ranges[i][0] - 1, jk); + printf("Second part: %llu\n", (unsigned long long)(ranges[i][0]-1)*XTUNING+(unsigned long long)jk); + } + } + free(scanned); + free(ranges); + } +} + +long dist(long x1, long y1, long x2, long y2) { + return abs(x1-x2) + abs(y1-y2); +} + +// We could do better if we want speed +// But I hope it is enough +int exists(long scanned[], int scanned_count, long x) { + for (int i = 0; i < scanned_count; i++) { + if (scanned[i] == x) { + return 1; + } + } + + return 0; +} + +unsigned overlap(long min1, long max1, long min2, long max2) { + if (max1 < min2 || max2 < min1) + return 0; + + return min(max1, max2) - max(min1, min2) + 1; +} diff --git a/day15/input.txt b/day15/input.txt new file mode 100644 index 0000000..0549898 --- /dev/null +++ b/day15/input.txt @@ -0,0 +1,27 @@ +Sensor at x=3523437, y=2746095: closest beacon is at x=3546605, y=2721324 +Sensor at x=282831, y=991087: closest beacon is at x=743030, y=-87472 +Sensor at x=1473740, y=3283213: closest beacon is at x=1846785, y=3045894 +Sensor at x=1290563, y=46916: closest beacon is at x=743030, y=-87472 +Sensor at x=3999451, y=15688: closest beacon is at x=3283637, y=-753607 +Sensor at x=1139483, y=2716286: closest beacon is at x=1846785, y=3045894 +Sensor at x=3137614, y=2929987: closest beacon is at x=3392051, y=3245262 +Sensor at x=2667083, y=2286333: closest beacon is at x=2126582, y=2282363 +Sensor at x=3699264, y=2920959: closest beacon is at x=3546605, y=2721324 +Sensor at x=3280991, y=2338486: closest beacon is at x=3546605, y=2721324 +Sensor at x=833202, y=92320: closest beacon is at x=743030, y=-87472 +Sensor at x=3961416, y=2485266: closest beacon is at x=3546605, y=2721324 +Sensor at x=3002132, y=3500345: closest beacon is at x=3392051, y=3245262 +Sensor at x=2482128, y=2934657: closest beacon is at x=1846785, y=3045894 +Sensor at x=111006, y=2376713: closest beacon is at x=354526, y=3163958 +Sensor at x=424237, y=2718408: closest beacon is at x=354526, y=3163958 +Sensor at x=3954504, y=3606495: closest beacon is at x=3392051, y=3245262 +Sensor at x=2275050, y=2067292: closest beacon is at x=2333853, y=2000000 +Sensor at x=1944813, y=2557878: closest beacon is at x=2126582, y=2282363 +Sensor at x=2227536, y=2152792: closest beacon is at x=2126582, y=2282363 +Sensor at x=3633714, y=1229193: closest beacon is at x=3546605, y=2721324 +Sensor at x=1446898, y=1674290: closest beacon is at x=2333853, y=2000000 +Sensor at x=3713985, y=2744503: closest beacon is at x=3546605, y=2721324 +Sensor at x=2281504, y=3945638: closest beacon is at x=1846785, y=3045894 +Sensor at x=822012, y=3898848: closest beacon is at x=354526, y=3163958 +Sensor at x=89817, y=3512049: closest beacon is at x=354526, y=3163958 +Sensor at x=2594265, y=638715: closest beacon is at x=2333853, y=2000000