day 11

examples/aoc2023/day11/part1.jou

@@ -0,0 +1,86 @@
+import "stdlib/io.jou"
+import "stdlib/mem.jou"
+import "stdlib/str.jou"
+import "stdlib/math.jou"
+
+
+class Input:
+    width: int
+    height: int
+    data: byte*
+
+    def duplicate_blank_lines(self) -> None:
+        self->data = realloc(self->data, 2*strlen(self->data) + 1)
+        assert self->data != NULL
+
+        y = 0
+        while y < self->height:
+            if strspn(&self->data[(self->width + 1)*y], ".") == self->width:
+                # duplicate row
+                blank_start = &self->data[(self->width + 1)*y]
+                next_start = &self->data[(self->width + 1)*(y+1)]
+                memmove(next_start, blank_start, strlen(blank_start) + 1)
+                y += 2
+                self->height++
+            else:
+                y++
+
+    def transpose(self) -> None:
+        old_content = strdup(self->data)
+        old_width = self->width
+        old_height = self->height
+        self->width = old_height
+        self->height = old_width
+
+        memset(self->data, '\n', strlen(self->data))
+        for x = 0; x < self->width; x++:
+            for y = 0; y < self->height; y++:
+                self->data[(self->width + 1)*y + x] = old_content[(old_width + 1)*x + y]
+
+        free(old_content)
+
+    # array is terminated by [-1, -1]
+    def get_hashtag_coords(self) -> int[2]*:
+        result: int[2]* = malloc(sizeof(result[0]) * (self->width * self->height + 1))
+        result_len = 0
+        for y = 0; y < self->height; y++:
+            for x = 0; x < self->width; x++:
+                if self->data[(self->width + 1)*y + x] == '#':
+                    result[result_len++] = [x, y]
+
+        result[result_len] = [-1, -1]
+        return result
+
+
+def manhattan_distance(a: int[2], b: int[2]) -> int:
+    return abs(a[0]-b[0]) + abs(a[1]-b[1])
+
+
+def main() -> int:
+    max_len = 100000
+    input = Input{data = calloc(1, max_len+1)}
+
+    f = fopen("sampleinput.txt", "r")
+    assert f != NULL
+    fread(input.data, 1, max_len, f)
+    fclose(f)
+
+    input.width = strcspn(input.data, "\n") as int
+    input.height = (strlen(input.data) as int) / (input.width + 1)
+
+    input.duplicate_blank_lines()
+    input.transpose()
+    input.duplicate_blank_lines()
+    input.transpose()
+
+    coords = input.get_hashtag_coords()
+
+    sum = 0
+    for i = 0; coords[i][0] != -1; i++:
+        for k = 0; k < i; k++:
+            sum += manhattan_distance(coords[i], coords[k])
+    printf("%d\n", sum)  # Output: 374
+
+    free(input.data)
+    free(coords)
+    return 0

examples/aoc2023/day11/part2.jou

@@ -0,0 +1,92 @@
+import "stdlib/io.jou"
+import "stdlib/mem.jou"
+import "stdlib/str.jou"
+
+
+class Input:
+    width: int
+    height: int
+    data: byte*
+
+    # returned array is terminated by -1
+    def find_blank_lines(self) -> int*:
+        result: int* = malloc(sizeof(result[0]) * (self->height + 1))
+        result_len = 0
+
+        for y = 0; y < self->height; y++:
+            if strspn(&self->data[(self->width + 1)*y], ".") == self->width:
+                result[result_len++] = y
+        result[result_len] = -1
+        return result
+
+    def transpose(self) -> None:
+        old_content = strdup(self->data)
+        old_width = self->width
+        old_height = self->height
+        self->width = old_height
+        self->height = old_width
+
+        memset(self->data, '\n', strlen(self->data))
+        for x = 0; x < self->width; x++:
+            for y = 0; y < self->height; y++:
+                self->data[(self->width + 1)*y + x] = old_content[(old_width + 1)*x + y]
+
+        free(old_content)
+
+    # returned array is terminated by -1
+    def get_hashtag_y_coords(self) -> int*:
+        result: int* = malloc(sizeof(result[0]) * (self->width * self->height + 1))
+        result_len = 0
+        for y = 0; y < self->height; y++:
+            for x = 0; x < self->width; x++:
+                if self->data[(self->width + 1)*y + x] == '#':
+                    result[result_len++] = y
+
+        result[result_len] = -1
+        return result
+
+
+def sum_vertical_distances(input: Input*) -> long:
+    hashtag_y_coords = input->get_hashtag_y_coords()
+    blank_lines = input->find_blank_lines()
+
+    result = 0L
+    for end = hashtag_y_coords; *end != -1; end++:
+        for start = hashtag_y_coords; start < end; start++:
+            for y = *start; y < *end; y++:
+                y_is_blank = False
+                for p = blank_lines; *p != -1; p++:
+                    if *p == y:
+                        y_is_blank = True
+                        break
+                if y_is_blank:
+                    # Change to 1000000 for actual input
+                    result += 100
+                    #result += 1000000
+                else:
+                    result += 1
+
+    free(hashtag_y_coords)
+    free(blank_lines)
+    return result
+
+
+def main() -> int:
+    max_len = 100000
+    input = Input{data = calloc(1, max_len+1)}
+
+    f = fopen("sampleinput.txt", "r")
+    assert f != NULL
+    fread(input.data, 1, max_len, f)
+    fclose(f)
+
+    input.width = strcspn(input.data, "\n") as int
+    input.height = (strlen(input.data) as int) / (input.width + 1)
+
+    result = sum_vertical_distances(&input)
+    input.transpose()
+    result += sum_vertical_distances(&input)
+    printf("%lld\n", result)  # Output: 8410
+
+    free(input.data)
+    return 0

examples/aoc2023/day11/sampleinput.txt

@@ -0,0 +1,10 @@
+...#......
+.......#..
+#.........
+..........
+......#...
+.#........
+.........#
+..........
+.......#..
+#...#.....