day6p2

day6p2/Makefile

@@ -0,0 +1,12 @@
+CFLAGS := -Wall -Wextra -std=c17 -D_GNU_SOURCE
+
+LIBS := glib-2.0
+CFLAGS += $(shell pkg-config --cflags $(LIBS))
+LDLIBS := $(shell pkg-config --libs $(LIBS))
+
+.PHONY: all
+all: main
+
+.PHONY: clean
+clean:
+	rm -f main

day6p2/input

@@ -0,0 +1,50 @@
+63, 142
+190, 296
+132, 194
+135, 197
+327, 292
+144, 174
+103, 173
+141, 317
+265, 58
+344, 50
+184, 238
+119, 61
+329, 106
+70, 242
+272, 346
+312, 166
+283, 351
+286, 206
+57, 225
+347, 125
+152, 186
+131, 162
+45, 299
+142, 102
+61, 100
+111, 218
+73, 266
+350, 173
+306, 221
+42, 284
+150, 122
+322, 286
+346, 273
+75, 354
+68, 124
+194, 52
+92, 44
+77, 98
+77, 107
+141, 283
+87, 306
+184, 110
+318, 343
+330, 196
+303, 353
+268, 245
+180, 220
+342, 337
+127, 107
+203, 127

day6p2/main.c

@@ -0,0 +1,98 @@
+#include <stdio.h>
+
+#include <glib.h>
+
+struct coord {
+    int x;
+    int y;
+};
+
+struct rect {
+    int x;
+    int y;
+    int w;
+    int h;
+};
+
+struct coord *parse_coords(const char *fname, unsigned *len)
+{
+    FILE *f = fopen(fname, "r");
+    if (!f) {
+        perror(fname);
+        return NULL;
+    }
+
+    GArray *array = g_array_new(FALSE, FALSE, sizeof(struct coord));
+    *len = 0;
+
+    char *line = NULL;
+    size_t line_len = 0;
+    while (getline(&line, &line_len, f) != -1) {
+        struct coord coord = {0};
+        if (sscanf(line, "%d, %d", &coord.x, &coord.y) != 2) continue;
+        g_array_append_val(array, coord);
+        (*len)++;
+    }
+
+    free(line);
+    fclose(f);
+    struct coord *res = (struct coord *)g_array_free(array, FALSE);
+    return res;
+}
+
+struct rect find_limit(struct coord *coords, unsigned len)
+{
+    struct rect rect = {0};
+    if (!len) return rect;
+
+    int xmax = rect.x = coords->x;
+    int ymax = rect.y = coords->y;
+
+    for (struct coord *coord = coords + 1; coord < coords + len; coord++) {
+        if (coord->x < rect.x) rect.x = coord->x;
+        if (coord->y < rect.y) rect.y = coord->y;
+        if (coord->x > xmax) xmax = coord->x;
+        if (coord->y > ymax) ymax = coord->y;
+    }
+
+    rect.w = xmax - rect.x + 1;
+    rect.h = ymax - rect.y + 1;
+
+    return rect;
+}
+
+int main()
+{
+    unsigned coords_len;
+    struct coord *coords = parse_coords("input", &coords_len);
+    if (!coords) return 1;
+
+    /*
+     * NOTE: This method I'm using to figure our the biggest non-infinite
+     *   influence range for a coordinate is suboptimal and won't work for all inputs.
+     * I could try to figure out how to calcluate it properly or a better algorithm
+     *   than checking literally each tile in a defined area, but I'm too lazy.
+     * If it works for my input it's fine ;)
+     */
+
+    struct rect limit = find_limit(coords, coords_len);
+    printf("%d,%d\n%d,%d\n",
+            limit.x, limit.y,
+            limit.x + limit.w - 1, limit.y + limit.h - 1);
+
+    unsigned total = 0;
+    for (int y = limit.y; y < limit.y + limit.h; y++) {
+        for (int x = limit.x; x < limit.x + limit.w; x++) {
+            unsigned dist = 0;
+            for (unsigned i = 0; i < coords_len; i++) {
+                dist += abs(coords[i].x - x) + abs(coords[i].y - y);
+            }
+            if (dist < 10000) total++;
+        }
+    }
+
+    printf("Area: %u\n", total);
+
+    g_free(coords);
+    return 0;
+}